16-Bit, 8-Channel Simultaneous Sampling Data Acquisition System ADAS3023 Data Sheet

16-Bit, 8-Channel Simultaneous Sampling Data Acquisition System ADAS3023 Data Sheet
16-Bit, 8-Channel Simultaneous
Sampling Data Acquisition System
ADAS3023
Data Sheet
FUNCTIONAL BLOCK DIAGRAM
Ease-of-use, 16-bit complete data acquisition system
Simultaneous sampling selection of 2, 4, 6, and 8 channels
Differential input voltage range: ±20.48 V maximum
High impedance 8-channel input: >500 MΩ
High input common-mode rejection: 95.0 dB
User-programmable input ranges
On-chip 4.096 V reference and buffer
No latency/pipeline delay (SAR architecture)
Serial 4-wire 1.8 V to 5 V SPI-/SPORT-compatible interface
40-lead LFCSP package (6 mm × 6 mm)
−40°C to +85°C industrial temperature range
VDDH AVDD DVDD
DIFF TO
COM
IN0
IN1
IN2
IN3
IN4
IN5
IN6
IN7
COM
VIO
RESET
PD
CNV
LOGIC/
INTERFACE
BUSY
CS
TRACK
AND
HOLD
PulSAR
ADC
PGIA
SCK
DIN
SDO
ADAS3023
REFIN
BUF
REF
VSSH AGND DGND REFx
APPLICATIONS
10942-001
FEATURES
Figure 1.
Multichannel data acquisition and system monitoring
Process control
Power line monitoring
Automated test equipment
Patient monitoring
Spectrum analysis
Instrumentation
GENERAL DESCRIPTION
The ADAS3023 is a complete 16-bit successive approximationbased analog-to-digital data acquisition system. This device is
capable of simultaneously sampling up to 500 kSPS for two
channels, 250 kSPS for four channels, 167 kSPS for six channels, and 125 kSPS for eight channels manufactured on the Analog
Devices, Inc., proprietary iCMOS® high voltage industrial process
technology.
The ADAS3023 integrates eight channels of low leakage track
and hold, a programmable gain instrumentation amplifier
(PGIA) stage with a high common-mode rejection offering four
differential input ranges, a precision low drift 4.096 V reference
and buffer, and a 16-bit charge redistribution successive approximation register (SAR) analog-to-digital converter (ADC). The
ADAS3023 can resolve differential input ranges of up to ±20.48 V
when using ±15 V supplies.
Rev. A
The ADAS3023 simplifies design challenges by eliminating
signal buffering, level shifting, amplification and attenuation,
common-mode rejection, settling time, or any of the other
analog signal conditioning challenges, yet allows for smaller
form factor, faster time to market, and lower costs.
The ADAS3023 is factory calibrated and its operation is
specified from −40°C to +85°C.
Table 1. Typical Input Range Selection
Single-Ended Signals1
0 V to 1 V
0 V to 2.5 V
0 V to 5 V
0 V to 10 V
1
Input Range, VIN
±1.28 V
±2.56 V
±5.12 V
±10.24 V
See Figure 39 and Figure 40 in the Analog Inputs section for more
information.
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ADAS3023
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1 Typical Application Connection Diagram .............................. 21 Applications ....................................................................................... 1 Analog Inputs ............................................................................. 21 Functional Block Diagram .............................................................. 1 Voltage Reference Input/Output .............................................. 22 General Description ......................................................................... 1 Power Supply............................................................................... 24 Revision History ............................................................................... 2 Power Dissipation Modes .......................................................... 24 Specifications..................................................................................... 3 Conversion Modes ..................................................................... 25 Timing Specifications .................................................................. 6 Digital Interface .............................................................................. 26 Absolute Maximum Ratings............................................................ 9 Conversion Control ................................................................... 26 ESD Caution .................................................................................. 9 RESET and Power-Down (PD) Inputs .................................... 26 Pin Configuration and Function Descriptions ........................... 10 Serial Data Interface ................................................................... 27 Typical Performance Characteristics ........................................... 12 General Timing .......................................................................... 28 Terminology .................................................................................... 17 Configuration Register .............................................................. 29 Theory of Operation ...................................................................... 19 Packaging and Ordering Information ......................................... 30 Overview...................................................................................... 19 Outline Dimensions ................................................................... 30 Operation..................................................................................... 19 Ordering Guide .......................................................................... 30 Transfer Functions...................................................................... 20 REVISION HISTORY
2/14—Rev. 0 to Rev. A
Changes to Table 2 ............................................................................ 5
Changes to Figure 38 ...................................................................... 21
5/13—Revision 0: Initial Version
Rev. A | Page 2 of 32
Data Sheet
ADAS3023
SPECIFICATIONS
VDDH = 15 V ± 5%, VSSH = −15 V ± 5%, AVDD = DVDD = 5 V ± 5%; VIO = 1.8 V to AVDD, Internal Reference VREF = 4.096 V, fS =
500 kSPS, all specifications TMIN to TMAX, unless otherwise noted.
Table 2.
Parameter
RESOLUTION
ANALOG INPUT (IN0 to IN7, COM)
Input Impedance
Operating Input Voltage Range 2
Differential Input Voltage Ranges, VIN
THROUGHPUT
Conversion Rate
Transient Response 3
DC ACCURACY
No Missing Codes
Integral Linearity Error
Differential Linearity Error
Transition Noise
Gain Error 4
Gain Error Match, Delta Mean
Gain Error Temperature Drift
Offset Error4
Offset Error Match, Delta Mean
Offset Error Temperature Drift
AC ACCURACY 5
Signal-to-Noise Ratio
Signal-to-Noise + Distortion (SINAD)
Test Conditions/Comments
Min
16
ZIN
VIN, on any single pin
VINX − COM
PGIA gain = 0.2, VIN = 40.96 V p-p
PGIA gain = 0.4, VIN = 20.48 V p-p
PGIA gain = 0.8, VIN = 10.24 V p-p
PGIA gain = 1.6, VIN = 5.12 V p-p
500
VSSH + 2.5
VDDH − 2.5
MΩ
V
−5VREF
−2.5VREF
−1.25VREF
−0.625VREF
+5VREF
+2.5VREF
+1.25VREF
+0.625VREF
V
V
V
V
0
0
0
0
500
250
167
125
820
kSPS
kSPS
kSPS
kSPS
ns
Two channels
Four channels
Six channels
Eight channels
Full-scale step
PGIA gain = 0.2, 0.4, or 0.8, COM = 0 V
PGIA gain = 1.6, COM = 0 V
All PGIA gains, COM = 0 V
PGIA gain = 0.2 or 0.4
PGIA gain = 0.8
PGIA gain = 1.6
External reference, all PGIA gains
External reference, all PGIA gains
External reference, PGIA gain = 0.2, 0.4, or 0.8
External reference, PGIA gain = 1.6
External reference, PGIA gain = 0.2
External reference, PGIA gain = 0.4
External reference, PGIA gain = 0.8
External reference, PGIA gain = 1.6
External reference, PGIA gain = 0.2, 0.4, 0.8, or 1.6
External reference, PGIA gain = 0.2 or 0.4, IN0 to IN7
External reference, PGIA gain = 0.8, IN0 to IN7
External reference, PGIA gain = 1.6, IN0 to IN7
Internal reference
fIN = 1 kHz, COM = 0 V
PGIA gain = 0.2
PGIA gain = 0.4
PGIA gain = 0.8
PGIA gain = 1.6
fIN = 1 kHz, two, four, six, and eight channels
PGIA gain = 0.2
PGIA gain = 0.4
PGIA gain = 0.8
PGIA gain = 1.6
Rev. A | Page 3 of 32
16
−2.5
−3
−0.95
Typ
±1
±1
±0.5
6
7
10
−0.075
−0.05
Max
+2.5
+3
+1.25
+0.075
+0.05
1
2
+12
+12
+10
250
+15
2
3
5
Unit 1
Bits
Bits
LSB
LSB
LSB
LSB
LSB
%FS
%FS
ppm/°C
ppm/°C
LSB
LSB
LSB
LSB
LSB
ppm/°C
ppm/°C
ppm/°C
−65
−85
−10
0
−15
0
0
0
−35
−45
0
130
±1
0.5
1.5
2.5
90.0
89.5
87.5
85.0
91.5
91.0
89.0
86.5
dB
dB
dB
dB
89.5
89.0
87.0
84.0
91.0
90.5
88.5
86.0
dB
dB
dB
dB
ADAS3023
Parameter
Dynamic Range
Total Harmonic Distortion
Spurious-Free Dynamic Range
Channel-to-Channel Crosstalk
DC Common-Mode Rejection Ratio
(CMRR)
−3 dB Input Bandwidth
INTERNAL REFERENCE
REFx Pins
Output Voltage
Output Current
Temperature Drift
Line Regulation
Internal Reference
Buffer Only
REFIN Output Voltage 6
Turn-On Settling Time
EXTERNAL REFERENCE
Voltage Range
Current Drain
DIGITAL INPUTS
Logic Levels
VIL
VIH
VIL
VIH
IIL
IIH
DIGITAL OUTPUTS 7
Data Format
VOL
VOH
POWER SUPPLIES
VIO
AVDD
DVDD
VDDH
VSSH
Data Sheet
Test Conditions/Comments
fIN = 1 kHz, −60 dB input
PGIA gain = 0.2
PGIA gain = 0.4
PGIA gain = 0.8
PGIA gain = 1.6
fIN = 1 kHz, all PGIA gains
fIN = 1 kHz, all PGIA gains
fIN = 1 kHz, all channels inactive
All channels
Min
Typ
91.0
90.5
88.0
86.0
92
91.5
89.5
87.0
−100
105
95
dB
dB
dB
dB
dB
dB
dB
95.0
95.0
95.0
95.0
8
dB
dB
dB
dB
MHz
PGIA gain = 0.2
PGIA gain = 0.4
PGIA gain = 0.8
PGIA gain = 1.6
−40 dBFS
TA = 25°C
TA = 25°C
REFEN bit = 1
REFEN bit = 0, REFIN pin = 2.5V
AVDD = 5 V ± 5%
AVDD = 5 V ± 5%
TA = 25°C
CREFIN, CREF1, CREF2 = 10 µF||0.1 µF
REFEN bit = 0
REFx input, REFIN = 0 V
REFIN input (buffered)
fS = 500 kSPS
VIO > 3 V
VIO > 3 V
VIO ≤ 3 V
VIO ≤ 3 V
4.088
2.495
4.000
4.096
250
±5
±1
20
4
2.5
100
4.096
2.5
100
−0.3
0.7 × VIO
−0.3
0.9 × VIO
−1
−1
Max
4.104
2.505
Unit 1
V
µA
ppm/°C
ppm/°C
μV/V
ppm
V
ms
4.104
2.505
V
V
µA
+0.3 × VIO
VIO + 0.3
+0.1 × VIO
VIO + 0.3
+1
+1
V
V
V
V
µA
µA
ISINK = +500 µA
ISOURCE = −500 µA
Twos complement
0.4
VIO − 0.3
V
V
VDDH > input voltage + 2.5 V
VSSH < input voltage − 2.5 V
1.8
4.75
4.75
14.25
−15.75
V
V
V
V
V
Rev. A | Page 4 of 32
5
5
15
−15
AVDD + 0.3
5.25
5.25
15.75
−14.25
Data Sheet
Parameter
IVDDH
IVSSH
IAVDD
IDVDD
IVIO
Power Supply Sensitivity
TEMPERATURE RANGE
Specified Performance
ADAS3023
Test Conditions/Comments
Two channels
Four channels
Six channels
Eight channels
PD = 1
Two channels
Four channels
Six channels
Eight channels
All PGIA gains, PD = 1
All PGIA gains, PD = 0, reference buffer enabled
All PGIA gains, PD = 0, reference buffer disabled
All PGIA gains, PD = 1
All PGIA gains, PD = 0
All PGIA gains, PD = 1
All PGIA gains, PD = 0, VIO = 3.3 V
All PGIA gains, PD = 1
External reference, TA = 25°C
PGIA gain = 0.2 or 0.4, VDDH/VSSH = ±15 V ± 5%
PGIA gain = 0.8, VDDH/VSSH = ±15 V ± 5%
PGIA gain = 1.6, VDDH/VSSH = ±15 V ± 5%
PGIA gain = 0.2 or 0.4, AVDD, DVDD = ±5 V ± 5%
PGIA gain = 0.8, AVDD, DVDD = ±5 V ± 5%
PGIA gain = 1.6, AVDD, DVDD = ±5 V ± 5%
TMIN to TMAX
Min
−5.5
−6.5
−10.0
−10.0
Typ
5.0
6.0
9.5
9.5
10.0
−5.0
−5.5
−8.5
−8.5
10.0
16.0
10.0
Unit 1
mA
mA
mA
mA
µA
mA
mA
mA
mA
µA
mA
mA
µA
mA
µA
mA
µA
±0.1
±0.2
±0.4
±1.0
±1.5
±2.5
LSB
LSB
LSB
LSB
LSB
LSB
100
2.5
100
Max
5.5
7.0
10.5
10.5
17.0
15.5
3
1.0
−40
+85
°C
The LSB unit means least significant bit. The weight of the LSB, referred to input, changes depending on the input voltage range. See the Programmable Gain section
for the LSB size.
2
Full-scale differential input ranges of ±2.56 V, ±5.12 V, ±10.24 V, and ±20.48 V are set by the configuration register.
3
If using the external multiplexer in front of the ADAS3023, it must be switched at least 820 ns prior to the rising edge of CNV.
4
See the Terminology section. These parameters are specified at ambient temperature with an external reference. All other influences of temperature and supply are
measured and specified separately.
5
All ac specifications expressed in decibels are referenced to the full-scale input range (FSR) and are tested with an input signal at 0.5 dB below full scale, unless
otherwise specified.
6
This is the output from the internal band gap reference.
7
There is no pipeline delay. Conversion results are available immediately after a conversion is completed.
1
Rev. A | Page 5 of 32
ADAS3023
Data Sheet
TIMING SPECIFICATIONS
VDDH = 15 V ± 5%, VSSH = −15 V ± 5%, AVDD = DVDD = 5 V ± 5%, VIO = 1.8 V to AVDD, Internal Reference VREF = 4.096 V, fS =
500 kSPS, all specifications TMIN to TMAX, unless otherwise noted. 1
Table 3.
Parameter
TIME BETWEEN CONVERSIONS
Warp 2 Mode, CMS = 0
Two Channels
Four Channels
Six Channels
Eight Channels
Normal Mode (Default), CMS = 1
Two Channels
Four Channels
Six Channels
Eight Channels
CONVERSION TIME: CNV RISING EDGE TO DATA AVAILABLE
Warp Mode, CMS = 0
Two Channels
Four Channels
Six Channels
Eight Channels
Normal Mode (Default), CMS = 1
Two Channels
Four Channels
Six Channels
Eight Channels
CNV
Pulse Width
CNV High to Hold Time (Aperture Delay)
CNV High to BUSY/SDO2 Delay
SCK
Period
Low Time
High Time
SCK Falling Edge to Data Remains Valid
SCK Falling Edge to Data Valid Delay
VIO > 4.5 V
VIO > 3 V
VIO > 2.7 V
VIO > 2.3 V
VIO > 1.8 V
CS/RESET/PD
CS/RESET/PD Low to SDO D15 MSB Valid
VIO > 4.5 V
VIO > 3 V
VIO > 2.7 V
VIO > 2.3 V
VIO > 1.8 V
CS/RESET/PD High to SDO High Impedance
CNV Rising to CS
Symbol
tCYC
Min
Typ
Max
Unit
2.0
4.0
6.0
8.0
1000
1000
1000
1000
µs
µs
µs
µs
2.1
4.1
6.1
8.1
1000
1000
1000
1000
µs
µs
µs
µs
1485
2850
4215
5580
1630
3340
5000
6700
ns
ns
ns
ns
1575
2940
4305
5670
1720
3430
5090
6790
ns
ns
ns
ns
520
ns
ns
ns
tCONV
tCNVH
tAD
tCBD
10
tSCK
tSCKL
tSCKH
tSDOH
tSDOV
tSDOV + 3
5
5
4
2
ns
ns
ns
ns
12
18
24
25
37
ns
ns
ns
ns
ns
7
8
10
15
20
25
ns
ns
ns
ns
ns
ns
ns
tEN
tDIS
tCCS
Rev. A | Page 6 of 32
5
Data Sheet
ADAS3023
Parameter
DIN
DIN Valid Setup Time from SCK Falling Edge
DIN Valid Hold Time from SCK Falling Edge
RESET/PD HIGH PULSE
1
2
Symbol
Min
tDINS
tDINH
tRH
4
4
5
See Figure 2 and Figure 3 for load conditions.
Exceeding the maximum time has an effect on the accuracy of the conversion (see the Conversion Modes section).
Circuit and Voltage Diagrams
500µA
IOL
1.4V
TO SDO
500µA
10942-002
CL
50pF
IOH
Figure 2. Load Circuit for Digital Interface Timing
70% VIO
30% VIO
2V OR VIO – 0.5V1
2V OR VIO – 0.5V1
0.8V OR 0.5V2
0.8V OR 0.5V2
12V IF VIO > 2.5V; VIO – 0.5V IF VIO < 2.5V.
20.8V IF VIO > 2.5V; 0.5V IF VIO < 2.5V.
Figure 3. Voltage Levels for Timing
Rev. A | Page 7 of 32
10942-003
tDELAY
tDELAY
Typ
Max
Unit
ns
ns
ns
ADAS3023
Data Sheet
Timing Diagrams
SOC
SOC
SOC
tCYC
EOC
EOC
tCONV
POWER
UP
PHASE
NOTE 1
NOTE 2
CONVERSION (n)
ACQUISITION (n + 1)
NOTE 1
CONVERSION (n + 1)
ACQUISITION (n + 2)
CNV
tCNVH
NOTE 4
tAD
NOTE 3
CS
1
16
1
16
1
16
1
16 1
16
1
16
NOTE 2
SCK
DIN
CFG (n + 2)
SDO
CH0
BUSY/
SDO2
CFG (n + 3)
CH1
CH7
CH0
CH1
CH7
DATA (n)
DATA (n + 1)
NOTES
1. DATA ACCESS CAN ONLY OCCUR AFTER CONVERSION. BOTH CONVERSION RESULT AND THE CFG REGISTER ARE UPDATED AT THE END OF THE CONVERSION (EOC).
2. A TOTAL OF 16 SCK FALLING EDGES ARE REQUIRED FOR CONVERSION RESULT. AN ADDITIONAL 16 EDGES AFTER THE LAST CONVERSION RESULT ON BUSY READS BACK THE CFG ASSOCIATED
WITH CONVERSION.
3. CS CAN BE HELD LOW OR CONNECTED TO CNV. CS IS SHOWN WITH FULL INDEPENDENT CONTROL.
4. FOR OPTIMAL PERFORMANCE, DATA ACCESS SHOULD NOT OCCUR DURING THE SAMPLING INSTANT. A MINIMUM TIME OF AT LEAST THE APERATURE DELAY, tAD, SHOULD LAPSE PRIOR TO DATA ACCESS.
10942-004
tCBD
Figure 4. General Timing Diagram with BUSY/SDO2 Disabled
SOC
SOC
SOC
tCYC
EOC
EOC
tCONV
POWER
UP
PHASE
NOTE 1
NOTE 1
CONVERSION (n)
ACQUISITION (n + 1)
CONVERSION (n + 1)
ACQUISITION (n + 2)
CNV
tCNVH
NOTE 4
tAD
NOTE 3
1
SCK
16
1
16 1
16 1
16
1
16 1
16 1
16 1
16
NOTE 2
DIN
CFG (n + 2)
SDO
CH0
CH1
CH2
CH3
CFG (n + 3)
CH0
CH1
CH2
CH3
BUSY/
SDO2
CH4
CH5
CH6
CH7
CH4
CH5
CH6
CH7
DATA (n + 1)
DATA (n)
NOTES
1. DATA ACCESS CAN ONLY OCCUR AFTER CONVERSION. BOTH CONVERSION RESULT AND THE CFG REGISTER ARE UPDATED AT THE END OF THE CONVERSION (EOC).
2. A TOTAL OF 16 SCK FALLING EDGES ARE REQUIRED FOR CONVERSION RESULT. AN ADDITIONAL 16 EDGES AFTER THE LAST CONVERSION RESULT ON BUSY READS BACK THE CFG ASSOCIATED
WITH CONVERSION.
3. CS CAN BE HELD LOW OR CONNECTED TO CNV. CS IS SHOWN WITH FULL INDEPENDENT CONTROL.
4. FOR OPTIMAL PERFORMANCE, DATA ACCESS SHOULD NOT OCCUR DURING THE SAMPLING INSTANT. A MINIMUM TIME OF AT LEAST THE APERATURE DELAY, tAD, SHOULD LAPSE PRIOR TO DATA ACCESS.
Figure 5. General Timing Diagram with BUSY/SDO2 Enabled
Rev. A | Page 8 of 32
10942-005
CS
Data Sheet
ADAS3023
ABSOLUTE MAXIMUM RATINGS
Table 4.
Parameter
Analog Inputs/Outputs
INx, COM to AGND
REFx to AGND
REFIN to AGND
REFN to AGND
Ground Voltage Differences
AGND, RGND, DGND
Supply Voltages
VDDH to AGND
VSSH to AGND
AVDD, DVDD, VIO to AGND
ACAP, DCAP, RCAP to AGND
Digital Inputs/Outputs
CNV, DIN, SCK, RESET, PD, CS
to DGND
SDO, BUSY/SDO2 to DGND
Internal Power Dissipation
Junction Temperature
Storage Temperature Range
Thermal Impedance
θJA (LFCSP)
θJC (LFCSP)
Rating
VSSH − 0.3 V to VDDH + 0.3 V
AGND − 0.3 V to AVDD + 0.3 V
AGND − 0.3 V to +2.7 V
±0.3 V
±0.3 V
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
ESD CAUTION
–0.3 V to +16.5 V
+0.3 V to −16.5 V
−0.3 V to +7 V
−0.3 V to +2.7 V
−0.3 V to VIO + 0.3 V
−0.3 V to VIO + 0.3 V
2W
125°C
−65°C to +125°C
44.1°C/W
0.28°C/W
Rev. A | Page 9 of 32
ADAS3023
Data Sheet
40 AGND
39 VDDH
38 VSSH
37 REFN
36 REFN
35 RGND
34 REF2
33 REF1
32 REFIN
31 RCAP
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
PIN 1
INDICATOR
ADAS3023
TOP VIEW
(Not to Scale)
30
29
28
27
26
25
24
23
22
21
AGND
AGND
AVDD
DVDD
ACAP
DCAP
AGND
AGND
DGND
DGND
NOTES
1. CONNECT THE EXPOSED PAD TO VSSH.
10942-006
CS
DIN
RESET
AGND
PD
SCK
VIO
SDO
BUSY/SDO2
CNV
11
12
13
14
15
16
17
18
19
20
IN0 1
IN1 2
IN2 3
IN3 4
AGND 5
IN4 6
IN5 7
IN6 8
IN7 9
COM 10
Figure 6. Pin Configuration
Table 5. Pin Function Descriptions
Pin No.
1 to 4
6 to 9
5, 14, 23,
24, 29,
30, 40
10
Mnemonic
IN0 to IN3
IN4 to IN7
AGND
Type 1
AI
AI
P
Description
Input Channel 0 to Input Channel 3.
Input Channel 4 to Input Channel 7.
Analog Ground. Connect AGND to the system analog ground plane.
COM
AI
11
CS
12
DIN
DI
13
RESET
DI
15
PD
DI
16
17
SCK
VIO
DI
P
18
SDO
DO
19
BUSY/SDO2
DO
20
21, 22
25
CNV
DGND
DCAP
DI
P
P
26
ACAP
P
IN0 to IN7 Common Channel Input. Input Channel IN0 to Input Channel IN7 are referenced to a common
point. The maximum voltage on this pin is ±10.24 V for all PGIA gains.
Chip Select. Active low signal. Enables the digital interface for writing and reading data. Use the CS pin when
sharing the serial bus. For a dedicated and simplified ADAS3023 serial interface, tie CS to DGND or CNV.
Data Input. DIN is the serial data input for writing the 16-bit configuration (CFG) word that is clocked
into the device on the SCK rising edges. The CFG is an internal register that is updated on the rising edge
of the next end of a conversion pulse, which coincides with the falling edge of BUSY/SDO2. The CFG
register is written into the device on the first 16 clocks after conversion. To avoid corrupting a conversion
due to digital activity on the serial bus, do not write data during a conversion.
Asynchronous Reset. A low-to-high transition resets the ADAS3023. The current conversion, if active, is
aborted and the CFG register is reset to the default state.
Power-Down. A low-to-high transition powers down the ADAS3023, minimizing the device operating
current. Note that PD must be held high until the user is ready to power on the device. After powering
on the device, the user must wait 100 ms until the reference is enabled and then wait for the completion
of one dummy conversion before the device is ready to convert. Note that the RESET pin remains low for
100 ns after the release of PD. See the Power-Down Mode section for more information.
Serial Clock Input. The DIN and SDO data sent to and from the ADAS3023 are synchronized with SCK.
Digital Interface Supply. Nominally, it is recommended that VIO be at the same voltage as the supply of
the host interface: 1.8 V, 2.5 V, 3.3 V, or 5 V.
Serial Data Output. The conversion result is output on this pin and synchronized to the SCK falling
edges. The conversion results are presented on this pin in twos complement format.
Busy/Serial Data Output 2. The converter busy signal is always output on the BUSY/SDO2 pin when CS is
logic high. If SDO2 is enabled when CS is brought low after the EOC, the SDO outputs the data. The
conversion result is output on this pin and synchronized to the SCK falling edges. The conversion results
are presented on this pin in twos complement format.
Convert Input. A conversion is initiated on the rising edge of the CNV pin.
Digital Ground. Connect DGND to the system digital ground plane.
Internal 2.5 V Digital Regulator Output. Decouple DCAP, an internally regulated output, using a 10 μF
and a 0.1 μF local capacitor.
Internal 2.5 V Analog Regulator Output. This regulator supplies power to the internal ADC core and to all
of the supporting analog circuits, except for the internal reference. Decouple this internally regulated
output (ACAP) using a 10 μF capacitor and a 0.1 μF local capacitor.
Rev. A | Page 10 of 32
Data Sheet
ADAS3023
Pin No.
27
Mnemonic
DVDD
Type 1
P
28
AVDD
P
31
RCAP
P
32
REFIN
33, 34
REF1, REF2
AI/O
35
36, 37
RGND
REFN
P
P
38
VSSH
P
39
VDDH
P
EP
N/A
Description
Digital 5 V Supply. Decouple the DVDD supply to DGND using a 10 μF capacitor and 0.1 μF local
capacitor.
Analog 5 V Supply. Decouple the AVDD supply to AGND using a 10 μF capacitor and 0.1 μF local
capacitor.
Internal 2.5 V Analog Regulator Output. RCAP supplies power to the internal reference. Decouple this
internally regulated output (RCAP) using a 10 μF capacitor and a 0.1 μF local capacitor.
Internal 2.5 V Band Gap Reference Output, Reference Buffer Input, or Reference Power-Down Input.
REF1 and REF2 must be tied together externally. See the Voltage Reference Input/Output section for
more information.
Reference Input/Output. Regardless of the reference method, REF1 and REF2 need individual
decoupling using external 10 μF ceramic capacitors connected as close to REF1, REF2, and REFN as
possible. See the Voltage Reference Input/Output section for more information.
Reference Supply Ground. Connect RGND to the system analog ground plane.
Reference Input/Output Ground. Connect the 10 μF capacitors that are on REF1 and REF2 to the REFN
pins, then connect the REFN pins to the system analog ground plane.
High Voltage Analog Negative Supply. Nominally, the supply of VSSH is −15 V. Decouple VSSH using a
10 μF capacitor and a 0.1 μF local capacitor. Connect the exposed pad to VSSH.
High Voltage Analog Positive Supply. Nominally, the supply of VDDH is 15 V. Decouple VDDH using a
10 μF capacitor and a 0.1 μF local capacitor.
Exposed Pad. Connect the exposed pad to VSSH.
AI = analog input, AI/O = analog input/output, DI = digital input, DO = digital output, P = power, and N/A means not applicable.
1
Rev. A | Page 11 of 32
ADAS3023
Data Sheet
TYPICAL PERFORMANCE CHARACTERISTICS
VDDH = 15 V, VSSH = −15 V, AVDD = DVDD = 5 V, VIO = 1.8 V to AVDD, unless otherwise noted.
400000
350000
300000
0.5
250000
24576
32768
40960
49152
57344 65536
CODE
0
0
0
0
962
1481
1
0
0
CODE IN HEX
Figure 10. Histogram of a DC Input at Code Center, PGIA Gain = 0.4
1.00
400000
0.75
350000
0.50
300000
0.25
250000
COUNT
0
PGIA GAIN = 0.8
fS = 500kSPS
INTERNAL REFERENCE
248346
188714
200000
–0.25
150000
–0.50
100000
43158
50000
2
0
0
8006
8007
908
8005
201
8004
0
8003
0
8002
CODE
0
8001
57344 65536
8000
49152
7FFF
40960
10942-102
32768
7FFE
18671
7FFD
CODE IN HEX
Figure 8. Differential Nonlinearity (DNL) vs. Code for All PGIA Gains
300000
350000
300000
278780
250000
200000
150000
150000
100000
100000
50000
50000
185455
171423
CODE IN HEX
9497
6254 238
806D
8069
56261
806C
450
806B
6
806A
0
8068
0
10942-103
0
8007
8000
0
8006
7FFF
7
8005
7FFE
6909
8004
83
8003
0
8002
0
8001
0
7FFD
0
23813
8067
70413
3
8071
190408
200000
8070
COUNT
250000
COUNT
PGIA GAIN = 1.6
fS = 500kSPS
INTERNAL REFERENCE
806F
350000
400000
PGIA GAIN = 0.2
fS = 500kSPS
INTERNAL REFERENCE
806E
400000
Figure 11. Histogram of a DC Input at Code Center, PGIA Gain = 0.8
CODE IN HEX
Figure 12. Histogram of a DC Input at Code Center, PGIA Gain = 1.6
Figure 9. Histogram of a DC Input at Code Center, PGIA Gain = 0.2
Rev. A | Page 12 of 32
10942-106
DNL (LSB)
Figure 7. Integral Nonlinearity (INL) vs. Code for All PGIA Gains
–0.75 FOR ALL PGIA GAINS
DNL MAX = 0.794
DNL MIN = –0.661
–1.00
0
8192 16384 24576
10942-104
16384
10942-105
8192
8001
0
8000
50000
7FFF
–1.5
97631
74640
7FFE
100000
7FFD
–1.0
7FFC
150000
7FFB
–0.5
–2.0
325285
200000
7FFA
0
PGIA GAIN = 0.4
fS = 500kSPS
INTERNAL REFERENCE
7FF9
COUNT
1.0
10942-101
INL (LSB)
1.5
7FF8
FOR ALL PGIA GAINS
INL MAX = 0.875
INL MIN = –1.216
7FF7
2.0
Data Sheet
ADAS3023
60
0
PGIA GAIN = 0.4
fS = 500kSPS
fIN = 1.12kHz
SNR = 91.2dB
SINAD = 91.1dB
THD = –107.0dB
SFDR = 106.0dB
INTERNAL REFERENCE
–20
50
AMPLITUDE (dBFS)
–40
30
20
0
1
2
3
4
5
–100
6
5
7
6
8
–140
2
3
9
10 11 12 13 14 15
2
3
REFERENCE DRIFT (ppm/°C)
–160
0
50
100
60
0
–20
AMPLITUDE (dBFS)
–40
28
20
–60
–80
–100
–120
13
10
–140
0
1
2
3
1
4
5
6
7
8
9
10 11 12 13 14 15
REFERENCE BUFFER DRIFT (ppm/°C)
–160
10942-117
0
2
0
50
100
0
PGIA GAIN = 0.2
fS = 500kSPS
fIN = 1.12kHz
SNR = 91.3dB
SINAD = 91.3dB
THD = –110.6dB
SFDR = 106.6dB
INTERNAL REFERENCE
–40
–60
–40
–80
–100
–60
–80
–100
–120
–140
–140
–160
50
100
150
200
FREQUENCY (kHz)
250
10942-107
–120
0
250
PGIA GAIN = 1.6
fS = 500kSPS
fIN = 1.12kHz
SNR = 87.3dB
SINAD = 87.2dB
THD = –103.0dB
SFDR = 106.0dB
INTERNAL REFERENCE
–20
AMPLITUDE (dBFS)
–20
200
Figure 17. 1 kHz FFT, PGIA Gain = 0.8
Figure 14. Reference Buffer Drift, Internal Reference
0
150
FREQUENCY (kHz)
10942-109
COUNT
40
AMPLITUDE (dBFS)
250
PGIA GAIN = 0.8
fS = 500kSPS
fIN = 1.12kHz
SNR = 89.7dB
SINAD = 89.6dB
THD = –104.0dB
SFDR = 105.0dB
INTERNAL REFERENCE
46
30
200
Figure 16. 1 kHz FFT, PGIA Gain = 0.4
Figure 13. Reference Drift, Internal Reference
50
150
FREQUENCY (kHz)
10942-108
3
0
–80
–120
11
10
10942-116
14 15 13 13
–60
–160
0
50
100
150
200
FREQUENCY (kHz)
Figure 18. 1 kHz FFT, PGIA Gain = 1.6
Figure 15. 1 kHz FFT, PGIA Gain = 0.2
Rev. A | Page 13 of 32
250
10942-110
COUNT
40
–80
CH1,
CH3,
CH4,
CH4,
CH4,
2 ACTIVE CHANNELS,
4 ACTIVE CHANNELS,
6 ACTIVE CHANNELS,
8 ACTIVE CHANNELS,
8 ACTIVE CHANNELS,
500kSPS,
200kSPS,
100kSPS,
100kSPS,
100kSPS,
PGIA GAIN =
PGIA GAIN =
PGIA GAIN =
PGIA GAIN =
PGIA GAIN =
0.8
0.8
0.8
0.2
0.4
VSSH CURRENT (mA)
CROSSTALK (dB)
–85
Data Sheet
–90
–95
–100
CH4, 8 ACTIVE CHANNELS, 100kSPS, PGIA GAIN = 0.8
CH4, 8 ACTIVE CHANNELS, 100kSPS, PGIA GAIN = 1.6
1k
10k
100k
1M
FREQUENCY (Hz)
10942-113
–105
100
–2.0
VSSH = –15V
–2.5
–3.0
2 ACTIVE CHANNELS, PGIA GAIN = 0.2
–3.5
2 ACTIVE CHANNELS, PGIA GAIN = 1.6
–4.0
–4.5
–5.0
4 ACTIVE CHANNELS, PGIA GAIN = 0.2
–5.5
4 ACTIVE CHANNELS, PGIA GAIN = 1.6
–6.0
–6.5
–7.0
8 ACTIVE CHANNELS, PGIA GAIN = 0.2
–7.5
6 ACTIVE CHANNELS, PGIA GAIN = 0.2
–8.0
–8.5
–9.0
8 ACTIVE CHANNELS, PGIA GAIN = 1.6
–9.5
–10.0
6 ACTIVE CHANNELS, PGIA GAIN = 1.6
–10.5
–11.0
10
100
1000
THROUGHPUT (kSPS)
Figure 19. Crosstalk vs. Frequency
110
Figure 22. VSSH Current vs. Throughput
20
PGIA GAIN = 0.2
PGIA GAIN = 0.4
PGIA GAIN = 0.8
PGIA GAIN = 1.6
100
AVDD = 5V
19
18
AVDD CURRENT (mA)
90
CMRR (dB)
10942-118
ADAS3023
80
70
60
17
16
INTERNAL REFERENCE
15
14
13
EXTERNAL REFERENCE
12
50
10
100
1k
10k
FREQUENCY (Hz)
10
10
THROUGHPUT (kSPS)
1000
Figure 23. AVDD Current vs. Throughput
3.5
DVDD = 5V
3.2
DVDD CURRENT (mA)
2.9
2.6
2.3
2.0
1.7
1.4
1.1
0.8
10942-115
VDDH CURRENT (mA)
Figure 20. CMRR vs. Frequency
11.0
6 ACTIVE CHANNELS, PGIA GAIN = 1.6
10.5 VDDH = 15V
10.0
8 ACTIVE CHANNELS, PGIA GAIN = 1.6
9.5
9.0
8.5
6 ACTIVE CHANNELS, PGIA GAIN = 0.2
8.0
8 ACTIVE CHANNELS, PGIA GAIN = 0.2
7.5
7.0
6.5
6.0
4 ACTIVE CHANNELS, PGIA GAIN = 1.6
5.5
5.0
4.5
4 ACTIVE CHANNELS, PGIA GAIN = 0.2
4.0
2 ACTIVE CHANNELS, PGIA GAIN = 1.6
3.5
3.0
2.5
2 ACTIVE CHANNELS, PGIA GAIN = 0.2
2.0
10
100
1000
100
THROUGHPUT (kSPS)
Figure 21. VDDH Current vs. Throughput
0.5
10
100
THROUGHPUT (kSPS)
Figure 24. DVDD Current vs. Throughput
Rev. A | Page 14 of 32
1000
10942-120
1
10942-114
40
10942-119
11
Data Sheet
ADAS3023
–4
130
120
110
90
100
80
70
60
50
40
30
20
0
–3
–4
CH0
CH4
CH1
CH5
CH2
CH6
CH3
CH7
130
10942-123
10942-124
120
110
100
90
80
70
60
50
40
30
20
–5
130
TEMPERATURE (°C)
–2
10
130
120
110
100
90
80
70
60
50
40
30
20
10
0
–10
–20
–30
–40
–50
–60
–120
10942-112
–115
0
–1
0
–110
1
–10
–105
2
–20
–100
3
TEMPERATURE (°C)
Figure 26. THD vs. Temperature
Figure 29. Normalized Offset Error Drift, PGIA Gain = 0.8
5
10
CH0
CH4
CH1
CH5
CH2
CH6
CH3
CH7
120
110
100
90
80
70
–10
60
130
120
110
100
90
80
70
60
50
40
30
20
10
0
–10
–20
–30
–40
–50
–60
TEMPERATURE (°C)
Figure 27. Normalized Offset Error Drift, PGIA GAin = 0.2
–8
50
CH3
CH7
40
CH2
CH6
30
CH1
CH5
–6
20
CH0
CH4
–5
10942-121
–4
–4
10
–3
0
–2
0
–2
2
–10
0
–1
4
–20
1
6
–30
2
PGIA GAIN = 1.6
EXTERNAL REFERENCE
fS = 125kSPS
TA = 25°C
8
–40
3
NORMALIZED OFFSET ERROR DRIFT (LSB)
PGIA GAIN = 0.2
EXTERNAL REFERENCE
fS = 125kSPS
TA = 25°C
4
–50
THD (dB)
–95
PGIA GAIN = 0.8
EXTERNAL REFERENCE
fS = 125kSPS
TA = 25°C
4
–30
–90
NORMALIZED OFFSET ERROR DRIFT (LSB)
CH3
CH7
5
PGIA GAIN = 0.4, fS = 500kSPS
PGIA GAIN = 0.8, fS = 250kSPS
PGIA GAIN = 0.8, fS = 125kSPS
PGIA GAIN = 1.6, fS = 167kSPS
–60
–85
CH2
CH6
Figure 28. Normalized Offset Error Drift, PGIA Gain = 0.4
NORMALIZED OFFSET ERROR DRIFT (LSB)
CH1,
CH2,
CH5,
CH3,
CH1
CH5
TEMPERATURE (°C)
Figure 25. SNR vs. Temperature
–80
CH0
CH4
–5
10942-122
TEMPERATURE (°C)
–3
10
130
120
110
90
100
80
70
60
50
40
30
20
0
10
–10
–20
–30
–40
–50
–60
80
10942-111
82
–2
–10
84
–1
–20
86
0
–30
88
1
–40
90
–50
92
2
–60
SNR (dB)
94
3
–40
96
PGIA GAIN = 0.4
EXTERNAL REFERENCE
fS = 125kSPS
TA = 25°C
4
–60
98
5
PGIA GAIN = 0.4, fS = 500kSPS
PGIA GAIN = 0.8, fS = 250kSPS
PGIA GAIN = 0.8, fS = 125kSPS
PGIA GAIN = 1.6, fS = 167kSPS
–50
CH1,
CH2,
CH5,
CH3,
NORMALIZED OFFSET ERROR DRIFT (LSB)
100
TEMPERATURE (°C)
Figure 30. Normalized Offset Error Drift, PGIA Gain = 1.6
Rev. A | Page 15 of 32
ADAS3023
Data Sheet
5
CH2
CH6
CH3
CH7
130
120
110
90
100
80
10942-127
CH1
CH5
TEMPERATURE (°C)
Figure 31. Normalized Gain Error Drift Error, PGIA Gain = 0.2
Figure 33. Normalized Gain Error Drift Error, PGIA Gain = 0.8
5
10
CH0
CH4
CH1
CH5
CH2
CH6
CH3
CH7
130
120
110
100
90
80
70
60
50
–10
TEMPERATURE (°C)
Figure 34. Normalized Gain Error Drift Error, PGIA Gain = 1.6
Rev. A | Page 16 of 32
10942-128
TEMPERATURE (°C)
Figure 32. Normalized Gain Error Drift Error, PGIA Gain = 0.4
–8
40
130
120
110
100
90
80
70
60
50
40
30
20
10
0
–10
–20
–30
–40
–50
–5
–6
30
CH3
CH7
20
CH2
CH6
10
CH1
CH5
0
CH0
CH4
10942-126
–4
–4
–10
–3
0
–2
–20
–2
2
–30
0
–1
4
–40
1
6
–50
2
PGIA GAIN = 1.6
EXTERNAL REFERENCE
fS = 125kSPS
TA = 25°C
8
–60
3
NORMALIZED GAIN ERROR DRIFT (LSB)
PGIA GAIN = 0.4
EXTERNAL REFERENCE
fS = 125kSPS
TA = 25°C
4
–60
NORMALIZED GAIN ERROR DRIFT (LSB)
CH0
CH4
–5
70
130
120
110
90
100
80
70
60
50
40
30
20
0
10
–10
–20
–30
–40
–50
–60
TEMPERATURE (°C)
–4
60
CH3
CH7
50
CH2
CH6
30
CH1
CH5
40
CH0
CH4
–5
–3
20
–4
–2
0
–3
–1
10
–2
0
–10
–1
1
–20
0
–30
1
2
–40
2
3
–50
3
PGIA GAIN = 0.8
EXTERNAL REFERENCE
fS = 125kSPS
TA = 25°C
4
–60
4
NORMALIZED GAIN ERROR DRIFT (LSB)
PGIA GAIN = 0.2
EXTERNAL REFERENCE
fS = 125kSPS
TA = 25°C
10942-125
NORMALIZED GAIN ERROR DRIFT (LSB)
5
Data Sheet
ADAS3023
TERMINOLOGY
Operating Input Voltage Range
Operating input voltage range is the maximum input voltage
range, including common-mode, which can be applied to the
input channels, IN0 to IN7, and COM.
Offset Error
Ideally, the MSB transition occurs at an input level that is ½ LSB
above analog ground. The offset error is the deviation of the
actual transition from that point.
Differential Input Voltage Range
Differential input voltage range is the maximum differential
full-scale input range. The value changes according to the
selected programmable gain setting.
Gain Error
Ideally, the last transition (from 011 … 10 to 011 … 11) occurs
for an analog voltage 1½ LSB below the nominal full scale. The
gain error is the deviation in LSB (or percentage of full-scale
range) of the actual level of the last transition from the ideal
level after the offset error is removed. Closely related is the fullscale error (also in LSB or percentage of full-scale range), which
includes the effects of the offset error.
Channel Off Leakage
Channel off leakage is the leakage current with the channel
turned off.
Channel On Leakage
Channel on leakage is the leakage current with the channel
turned on.
Common-Mode Rejection Ratio (CMRR)
CMRR is computed as the ratio of the signal magnitude of the
converted result, referred to input, in the converted result to the
amplitude of the common modulation signal applied to an input
pair, expressed in decibels. CMRR is a measure of the ability of
the ADAS3023 to reject signals, such as power line noise, that are
common to the inputs. This specification is tested and specified
for all input channels, IN0 to IN7, with respect to COM.
Transient Response
Transient response is a measure of the time required for the
ADAS3023 to properly acquire the input after a full-scale step
function is applied to the system.
Least Significant Bit (LSB)
The LSB is the smallest increment that can be represented by a
converter. For a fully differential input ADC with N bits of
resolution, the LSB expressed in volts is
2V
LSB (V) = REF
2N
Integral Nonlinearity Error (INL)
INL refers to the deviation of each individual code from a line
drawn from negative full scale through positive full scale. The
point used as negative full scale occurs ½ LSB before the first
code transition. Positive full scale is defined as a level 1½ LSB
beyond the last code transition. The deviation is measured from
the middle of each code to the true straight line (see Figure 37).
Aperture Delay
Aperture delay is the measure of the acquisition performance. It
is the time between the rising edge of the CNV input and the point
at which the input signal is held for a conversion.
Dynamic Range
Dynamic range is the ratio of the rms value of the full scale to
the total rms noise measured with a −60 dBFS input signal applied
to the inputs. The value for dynamic range is expressed in decibels.
Signal-to-Noise Ratio (SNR)
SNR is the ratio of the rms value of the actual input signal to the
rms sum of all other spectral components below the Nyquist
frequency, excluding harmonics and dc. The value for SNR is
expressed in decibels.
Signal-to-(Noise + Distortion) Ratio (SINAD)
SINAD is the ratio of the rms value of the actual input signal to
the rms sum of all other spectral components below the Nyquist
frequency, including harmonics but excluding dc. The value for
SINAD is expressed in decibels.
Total Harmonic Distortion (THD)
THD is the ratio of the rms sum of the first five harmonic
components to the rms value of a full-scale input signal
expressed in decibels.
Spurious-Free Dynamic Range (SFDR)
SFDR is the difference, in decibels, between the rms amplitude
of the input signal and the peak spurious signal.
Differential Nonlinearity Error (DNL)
In an ideal ADC, code transitions are 1 LSB apart. DNL is the
maximum deviation from this ideal value. DNL is often specified in
terms of resolution for which no missing codes are guaranteed.
Rev. A | Page 17 of 32
ADAS3023
Data Sheet
Channel-to-Channel Crosstalk
Channel-to-channel crosstalk is a measure of the level of crosstalk
between any channel and all other channels. The crosstalk is
measured by applying a dc input to the channel under test and
applying a full-scale, 10 kHz sine wave signal to all other channels.
The crosstalk is the amount of signal that leaks into the test channel
expressed in decibels.
Reference Voltage Temperature Coefficient
The reference voltage temperature coefficient is derived from
the typical shift of output voltage at 25°C on a sample of devices
at the maximum and minimum reference output voltage (VREF)
measured at TMIN, TA (25°C), and TMAX expressed in ppm/°C.
TCV REF (ppm/°C) =
V REF ( Max ) – V REF ( Min)
V REF (25°C ) × (T MAX – TMIN )
× 10 6
where:
VREF (Max) is the maximum VREF at TMIN, TA (25°C), or TMAX.
VREF (Min) is the minimum VREF at TMIN, TA (25°C), or TMAX.
VREF (25°C) = VREF at 25°C.
TMAX = +85°C.
TMIN = −40°C.
Rev. A | Page 18 of 32
Data Sheet
ADAS3023
THEORY OF OPERATION
OVERVIEW
The ADAS3023 offers true high impedance inputs in a differential
structure and rejects common-mode signals present on the inputs.
This architecture does not require additional input buffers (op
amps) that are usually required for signal buffering, level shifting,
amplification, attenuation, and kickback reduction when using
switched capacitor-based SAR ADCs.
The ADAS3023 is a 16-bit, 8-channel simultaneous system on a
single chip that integrates the typical components used in a data
acquisition system in one easy to use, programmable device. It is
capable of converting two channels simultaneously up to 500,000
samples per second (500 kSPS) throughput. The ADAS3023
features
•
•
High impedance inputs
High common-mode rejection
An 8-channel, low leakage track and hold
A programmable gain instrumentation amplifier (PGIA)
with four selectable differential input ranges from ±2.56 V
to ±20.48 V
A 16-bit PulSAR® ADC with no missing codes
An internal, precision, low drift 4.096 V reference and
buffer
The conversion results are output in twos complement format
on the serial data output (SDO) and through an optional secondary
serial data output on the BUSY/SDO2 pin. The digital interface
uses a dedicated chip select (CS) to control data access to and
from the ADAS3023 together with a BUSY/SDO2 output, asynchronous reset (RESET), and power-down (PD) inputs.
The internal reference of the ADAS3023 uses an internal temperature compensated 2.5 V output band gap reference, followed by
a precision buffer amplifier to provide the 4.096 V high precision
system reference.
The ADAS3023 uses the Analog Devices patented high voltage
iCMOS process allowing up to a ±20.48 V differential input voltage
range when using ±15 V supplies, which makes the device suitable
for industrial applications.
All of these components are configured through a serial (SPIcompatible), 16-bit CFG register. Configuration and conversion
results are read after the conversions are completed.
The device is housed in a small 6 mm × 6 mm, 40-lead LFCSP
package and can operate over the industrial temperature range of
−40°C to +85°C. A typical discrete multichannel data acquisition
system containing similar circuitry requires more space on the
circuit board than the ADAS3023. Therefore, advantages of the
ADAS3023 solution include a reduced footprint and less complex
design requirements, leading to faster time to market and lower costs.
The ADAS3023 requires a minimum of three power supplies
+15 V, −15 V, and +5 V. Internal low dropout regulators provide
the necessary 2.5 V system voltages that must be decoupled
externally via dedicated pins (ACAP, DCAP, and RCAP). The
ADAS3023 can be interfaced to any 1.8 V to 5 V digital logic
family using the dedicated VIO logic level voltage supply (see
Table 9).
OPERATION
A rising edge on the CNV pin initiates a conversion and changes
the ADAS3023 from track to hold. In this state, the ADAS3023
performs the analog signal conditioning and conversion. When
the signal conditioning is completed, the ADAS3023 returns to
the track state while, at the same time, quantizes the sample. This
two-tiered process satisfies the necessary settling time requirement
and achieves a fast throughput rate of up to 500 kSPS with 16-bit
accuracy.
The analog circuitry of the ADAS3023 consists of a high
impedance, low leakage, track-and-hold PGIA with a high
common-mode rejection that can accept the full-scale differential voltages of ±2.56 V, ±5.12 V, ±10.24 V, and ±20.48 V (see
Figure 15). The ADAS3023 can be configured to sample two,
four, six, or eight channels simultaneously.
VDDH AVDD DVDD
DIFF TO
COM
IN0
IN1
IN2
IN3
IN4
IN5
IN6
IN7
COM
VIO
RESET
PD
CNV
LOGIC/
INTERFACE
BUSY
CS
TRACK
AND
HOLD
PulSAR
ADC
PGIA
SCK
DIN
SDO
ADAS3023
REFIN
BUF
REF
VSSH AGND DGND REFx
Figure 35. Simplified Block Diagram
Rev. A | Page 19 of 32
10942-007
•
•
•
•
Digital control of the programmable gain setting of each
channel input is set via the configuration (CFG) register.
ADAS3023
Data Sheet
TRANSFER FUNCTIONS
CONVERSION
ACQUISITION
PHASE
10942-008
CNV
Figure 36. System Timing
Regardless of the type of signal, (single-ended symmetric or
asymmetric), the ADAS3023 converts all signals present on the
enabled inputs and COM pin in a differential fashion identical
to an industry-standard difference or instrumentation amplifier.
The conversion results are available after the conversion is complete
and can be read back at any time before the end of the next conversion. Avoid reading back data during the quiet period, indicated
by BUSY/SDO2 being active high. Because the ADAS3023 has
an on-board conversion clock, the serial clock (SCK) is not
required for the conversion process; it is only required to
present results to the user.
The ideal transfer characteristic for the ADAS3023 is shown in
Figure 37. The inputs are configured for differential input ranges
and the data outputs are in twos complement format, as listed in
Table 6.
TWOS
STRAIGHT
COMPLEMENT
BINARY
011...111
111...111
011...110
011...101
111...110
111...101
100...010
000...010
100...001
000...001
100...000
000...000
–FSR
–FSR + 1LSB
–FSR + 0.5LSB
+FSR – 1LSB
+FSR – 1.5LSB
ANALOG INPUT
Figure 37. ADC Ideal Transfer Function
Table 6. Output Codes and Ideal Input Voltages
Description
FSR − 1 LSB
Midscale + 1 LSB
Midscale
Midscale − 1 LSB
−FSR + 1 LSB
−FSR
Differential Analog Inputs, VREF = 4.096 V
(32,767 × VREF)/(32,768 × PGIA gain)
(VREF/(32,768 × PGIA gain))
0
−(VREF/(32,768 × PGIA gain))
−(32,767 × VREF)/(32,768 × PGIA gain)
−VREF × PGIA gain
Rev. A | Page 20 of 32
Digital Output Code
(Twos Complement Hex)
0x7FFF
0x0001
0x0000
0xFFFF
0x8001
0x8000
10942-009
tACQ
ADC CODE
tCYC
tCONV
Data Sheet
ADAS3023
D2
+
L2
47µH
COUT3
4.7µF
C2
1µF
+
1.78Ω
RFILT
L1
47µH
+5V
VIN = +5V
+
D1
CIN +
1µF
COUT1 +
1µF
+15V
COUT2 +
2.2µF
VDDH
AVDD DVDD
VIO
RESET
PD
ADP1613
CC2
10pF
R C1
100kΩ
DIFF TO
COM
RS1
0Ω
IN0
IN1
IN2
IN3
IN4
IN5
IN6
IN7
SS
FB
FREQ
EN
VIN
GND
SW
CNV
LOGIC/
INTERFACE
CS
RF2
4.22kΩ
CSS +
1µF
SCK
TRACK
AND
HOLD
PulSAR
ADC
PGIA
DIN
SDO
REFIN
BUF
COM
CV5 + RS2
1µF
DNI
BUSY
ADAS3023
REF
Z1
DNI
VSSH
REFx
AGND DGND
4.096V
–15V
RF1B
47.5kΩ
+5V
+5V
+
–
AD8031
ADR434
10942-200
50kΩ
COMP
+
L3
1µF
REN
ENABLE
C C1 +
12nF
C1
1µF
RB0
1Ω
Figure 38. Complete 5 V, Single-Supply, 8-Channel Data Acquisition System with PGIA
TYPICAL APPLICATION CONNECTION DIAGRAM
TRACK
AND
HOLD
INx OR COM
PGIA
CPIN
VSSH
10942-010
As shown in Figure 38, the ADP1613 is used in an inexpensive
SEPIC-Ćuk topology, which is an ideal candidate for providing
the ADAS3023 with the necessary high voltage ±15 V robust
supplies (at 20 mA) and low output ripple (3 mV maximum) from
an external 5 V supply. The ADP1613 satisfies the specification
requirements of the ADAS3023 using minimal external components yet achieves greater than 86% efficiency. See the CN-0201
circuit note for complete information about this test setup.
VDDH
AGND
ANALOG INPUTS
Input Structure
Figure 39. Equivalent Analog Input Circuit
The ADAS3023 uses a differential input structure between each
of the channel inputs, IN0 to IN7, and a common reference
(COM), all of which sample simultaneously.
Figure 39 shows an equivalent circuit of the inputs. The diodes
provide ESD protection for the analog inputs (IN0 to IN7) and
COM from the high voltage supplies (VDDH and VSSH). Ensure
that the analog input signal does not exceed the supply rails by
more than 0.3 V because this can cause the diodes to become
forward-biased and to start conducting current. The voltages
beyond the absolute maximum ratings may cause permanent
damage to the ADAS3023 (see Table 4).
Programmable Gain
The ADAS3023 incorporates a programmable gain instrumentation amplifier (PGIA) with four selectable ranges. The
PGIA settings are specified in terms of the maximum absolute
differential input voltage across an input pin and the COM pin,
for example INx to COM. The power on and default conditions
are preset to the ±20.48 V (PGIA = 11) input range.
Note that because the ADAS3023 can use any input type, such
as bipolar single-ended and pseudo bipolar, setting the PGIA is
important to make full use of the allowable input span.
Rev. A | Page 21 of 32
ADAS3023
Data Sheet
Table 7 describes each differential input range and the corresponding LSB size, PGIA bit settings, and PGIA gain.
INx+
+2.56V
0V
Table 7. Differential Input Ranges, LSB Size, and PGIA
Settings
Differential Input Ranges,
INx − COM (V)
±20.48
±10.24
±5.12
±2.56
LSB (μV)
625
312.5
156.3
78.13
Common-Mode Operating Range
The differential input common-mode range changes according
to the input range selected for a given channel and the high voltage power supplies. Note that the operating input voltage of
any input pin, as defined in the Specifications section, requires
a minimum of 2.5 V of headroom from the VDDH/VSSH
supplies or
The following sections offer some examples of setting the PGIA
for various input signals. Note that the ADAS3023 always takes
the difference between the INx and COM signals.
Single-Ended Signals with a Nonzero DC Offset
(Asymmetrical)
When a 5.12 V p-p signal with a 2.56 V dc offset is connected to
one of the inputs (INx+) and the dc ground sense of the signal
is connected to COM, the PGIA gain configuration is set to 01
for the ±5.12 V range because the maximum differential voltage
across the inputs is +5.12 V. This scenario uses only half the
codes available for the transfer function.
5.12V p-p
ADAS3023
VOFF
COM
COM
10942-011
VOFF
0V
10942-012
Figure 41. Optimal Single-Ended Configuration Using All Codes
Notice that the voltages in the examples are not integer values
due to the 4.096 V reference and the scaling ratios of the PGIA.
The maximum allowed dc offset voltage on the COM input pin
for various PGIA gains in this case is shown in Table 8.
Table 8. DC Offset Voltage on COM Input and PGIA
Settings1
PGIA Gain (V/V)
0.2
0.4
0.8
1.6
DC Offset Voltage on COM (V)
0
0
±5.12
±7.68
Full-scale signal on INx.
VOLTAGE REFERENCE INPUT/OUTPUT
The ADAS3023 allows the choice of an internal reference, an
external reference using an internal buffer, or an external
reference.
The internal reference of the ADAS3023 provides excellent
performance and can be used in nearly any application. Setting
the reference selection mode uses the internal reference enable
bit, REFEN, and the REFIN pin as described in the following
sections (Internal Reference, External Reference and Internal
Buffer, External Reference, and Reference Decoupling).
Internal Reference
The precision internal reference is factory trimmed and is
suitable for most applications.
INx+
+5.12V
COM
1
(VSSH + 2.5 V) ≤ INx/COM ≤ (VDDH – 2.5 V)
INx+
ADAS3023
5.12V p-p
COM
–2.56V
PGIA
Gain
(V/V)
0.2
0.4
0.8
1.6
PGIA
CFG
11
00
01
10
INx+
Figure 40. Typical Single-Ended Unipolar Input Using Only Half of the Codes
Single-Ended Signals with a 0 V DC Offset (Symmetrical)
Compared with the example in the Single-Ended Signals with a
Nonzero DC Offset (Asymmetrical) section, a better solution
for single-ended signals, when possible, is to remove as much
differential dc offset between INx and COM such that the average
voltage is 0 V (symmetrical around the ground sense). The
differential voltage across the inputs is never greater than
±2.56 V, and the PGIA gain configuration is set for a ±2.56 V
range (10). This scenario uses all of the codes available for the
transfer function, making full use of the allowable differential
input range.
Setting the REFEN bit in the CFG register to 1 (default) enables
the internal reference and produces 4.096 V on the REF1 and
REF2 pins; this 4.096 V output serves as the main system reference.
The unbuffered 2.5 V (typical) band gap reference voltage is
output on the REFIN pin, which requires an external parallel
combination of 10 μF and 0.1 μF capacitors to reduce the noise
on the output. Because the current output of REFIN is limited,
it can be used as a source when followed by a suitable buffer,
such as the AD8031. Note that excessive loading of the REFIN
output lowers the 4.096 V system reference because the internal
amplifier uses a fixed gain.
The internal reference output is trimmed to the targeted value
of 4.096 V with an initial accuracy of ±8 mV. The reference is
also temperature compensated to provide a typical drift of
±5 ppm/°C.
When the internal reference is used, decouple the ADAS3023,
as shown in Figure 42. Note that both the REF1 and REF2 connections are shorted together and externally decoupled with
Rev. A | Page 22 of 32
Data Sheet
ADAS3023
loading for op amps usually refers to the ability of the amplifier
to remain marginally stable in ac applications but can also play
a role in dc applications, such as a reference source.
suitable decoupling on the REFIN output and the RCAP
internally regulated supply.
0.1µF
0.1µF
0.1µF
10µF
10µF
REFN
REF2
Keep in mind that the reference source sees the dynamics of the
bit decision process on the reference pins and further analysis
beyond the scope of this data sheet may be required.
10µF
REFN
REF1
REFN
REFIN
REFERENCE
SOURCE = 4.096V
BAND
GAP
0.1µF
RCAP
1µF
10µF
10942-013
ADAS3023
RGND
REFN
0.1µF
10µF
REF2
REFN
REFIN
REF1
Figure 42. 4.096V Internal Reference Connection
ADAS3023
The external reference and internal buffer are useful where a
common system reference is used or when improved drift
performance is required.
Setting Bit REFEN to 0 disables the internal band gap reference,
allowing the user to provide an external voltage reference (2.5 V
typical) to the REFIN pin. The internal buffer remains enabled,
thus reducing the need for an external buffer amplifier to generate
the main system reference. Where REFIN = 2.5 V and REF1 and
REF2 output 4.096 V, this serves as the main system reference.
For this configuration, connect the external source, as shown in
Figure 43. Any type of 2.5 V reference can be used in this configuration (low power, low drift, small package, and so forth) because
the internal buffer handles the dynamics of the ADAS3023
reference requirements.
REFN
0.1µF
10µF
REF2
REFN
ADAS3023
0.1µF
10µF
REF1
REFN
BAND
GAP
REFERENCE
SOURCE = 2.5V
REFIN
RCAP
1µF
RGND
10942-014
0.1µF
10µF
Figure 43. External Reference Using Internal Buffer
External Reference
For applications that require a precise, low drift, 4.096 V
reference, an external reference can be used. Note that in this
mode, disabling the internal buffer requires setting REFEN to 0,
and driving or connecting REFIN to AGND; thus, both hardware
and software control are necessary. Attempting to drive the REF1
and REF2 pins alone prior to disabling the internal buffer can
cause source/sink contention in the outputs of the driving
amplifiers.
Connect the precision 4.096 V reference directly to REF1 and
REF2, which are the main system reference (see Figure 44); two
recommended references are the ADR434 or ADR444.
If an op amp is used as an external reference source, take note of
the concerns regarding driving capacitive loads. Capacitive
BAND
GAP
RGND
RCAP
1µF
10942-015
External Reference and Internal Buffer
Figure 44. External Reference
Reference Decoupling
With any of the reference topologies described in the Voltage
Reference Input/Output section, the REF1 and REF2 reference
pins of the ADAS3023 have dynamic impedances and require
sufficient decoupling, regardless of whether the pins are used as
inputs or outputs. This decoupling usually consists of a low ESR
capacitor connected to each REF1 and REF2 pin and to the accompanying REFN return paths. Ceramic chip capacitors (X5R, 1206
size) are recommended for decoupling in all of the reference
topologies described in the Voltage Reference Input/Output
section.
The placement of the reference decoupling capacitors plays an
important role in system performance. Using thick printed circuit
board (PCB) traces, mount the decoupling capacitors on the same
side as the ADAS3023, close to the REF1 and REF2 pins. Route the
return paths to the REFN inputs that, in turn, connect to the analog
ground plane of the system. When it is necessary to connect to an
internal PCB, minimize the resistance of the return path to ground
by using as many through vias as possible.
Using the shortest distance and several vias, connect the REFN
and RGND inputs to the analog ground plane of the system,
preferably adjacent to the solder pads. One common mistake is
to route these traces to an individual trace that connects to the
ground of the system. This can introduce noise, which may
adversely affect the LSB sensitivity. To prevent such noise, use
PCBs with multiple layers, including ground planes, rather than
using single or double sided boards.
Smaller reference decoupling capacitor values (as low as 2.2 µF)
can be used with little impact, mainly on DNL and THD. Furthermore, there is no need for an additional lower value ceramic
decoupling capacitor (for example, 100 nF) that is common in
decoupling schemes for high frequency noise rejection.
For applications that use multiple ADAS3023 devices or other
PulSAR ADCs, using the internal reference buffer is most effective
Rev. A | Page 23 of 32
ADAS3023
Data Sheet
to buffer the external reference voltage and, thereby, reduce SAR
conversion crosstalk.
VIO is the variable digital input/output supply and allows direct
interface with any logic between 1.8 V and 5 V (DVDD supply
maximum). To reduce the supplies that are required, VIO can,
alternatively, be connected to DVDD when DVDD is supplied
from the analog supply through an RC filter. The recommended
low dropout regulators are ADP3334, ADP1715, ADP7102, and
ADP7104 for the AVDD, DVDD, and VIO supplies. Note that
the user must bring up the ADAS3023 power supplies in the
following sequence:
The voltage reference temperature coefficient (TC) directly
affects the full-scale accuracy of the system; therefore, in
applications where full-scale accuracy is crucial, care must be
taken with the TC. For example, a ±15 ppm/°C TC of the
reference changes the full-scale accuracy by ±1 LSB/°C.
POWER SUPPLY
The ADAS3023 uses five supplies: AVDD, DVDD, VIO, VDDH,
and VSSH (see Table 9). Note that the ACAP, DCAP, and RCAP
pins are for informational purposes only because they are the
outputs of the internal supply regulators.
Table 9. Supplies
Mnemonic
AVDD
DVDD
Function
Analog 5 V core
Digital 5 V core
VIO
Digital input/output
VDDH
VSSH
Positive high voltage
Negative high
voltage
Analog 2.5 V core
Digital 2.5 V core
Analog 2.5 V core
ACAP
DCAP
RCAP
Required
Yes
Yes, or can connect to
AVDD
Yes, and can connect to
DVDD (for the 5 V level)
Yes, +15 V typical
Yes, −15 V typical
The high voltage bipolar supplies, VDDH and VSSH, are
required and must be at least 2.5 V larger than the maximum
operating input voltage. Specifically, any operating input voltage
(as defined in Table 2) of an input pin requires 2.5 V of headroom
from the VDDH/VSSH supplies or
(VSSH + 2.5 V) ≤ INx/COM ≤ (VDDH − 2.5 V)
No, on chip
No, on chip
No, on chip
Sufficient decoupling of these supplies is also required, consisting
of at least a 10 μF capacitor and 100 nF capacitor on each supply.
POWER DISSIPATION MODES
The ADAS3023 offers two power dissipation modes: fully
operational mode and power-down mode.
The AVDD and DVDD pins supply the ADAS3023 analog and
digital cores, respectively. Sufficient decoupling of these supplies is
required, consisting of at least a 10 μF capacitor and 100 nF capacitor on each supply. Place the 100 nF capacitors as close as possible
to the ADAS3023. To reduce the number of supplies that are
required, supply the DVDD from the analog supply by connecting
a simple RC filter between AVDD and DVDD, as shown in
Figure 45.
20Ω
10µF
+
10µF
100nF
+1.8V TO +5V
DIGITAL I/O
SUPPLY
10µF
–15V
VIO
VDDH
+
+
Power-Down Mode
100nF
100nF
10µF
+
ADAS3023
100nF
DGND
VSSH
10942-016
10µF
In fully operational mode, the ADAS3023 can perform the
conversions normally.
100nF
AVDD AGND DVDD DGND
+15V
Fully Operational Mode
+5V DIGITAL
SUPPLY
+
Figure 45. Supply Connections
VIO
VDDH
VSSH
DVDD
AVDD
REFx
High Voltage Supplies
Core Supplies
+5V ANALOG
SUPPLY
1.
2.
3.
4.
5.
6.
To minimize the operating currents of the device when it is idle,
place the device in full power-down mode by bringing the PD
input high; this places the ADAS3023 into a deep sleep mode in
which CNV activity is ignored and the digital interface is inactive.
Refer to the RESET and Power-Down (PD) Inputs section for
timing details. In deep sleep mode, the internal regulators
(ACAP, RCAP, and DCAP) and the voltage reference are
powered down.
To reestablish operation, return PD to logic low. Note that, before
the device can operate at the specified performance, the reference
voltage must charge up the external reservoir capacitor(s) and be
allowed the specified settling time. RESET must be applied after
returning PD to low to restore the ADAS3023 digital core, including the CFG register, to its default state. Therefore, the desired CFG
must be rewritten to the device and one dummy conversion must
be completed before the device operation is restored to the configuration programmed prior to PD assertion. Note that when using
the internal reference, sufficient time is required to settle it to
the nominal value. For a typical connection, it requires 100 ms
to settle to the nominal value (see Figure 41).
Rev. A | Page 24 of 32
Data Sheet
ADAS3023
CONVERSION MODES
Normal Mode (CMS = 1, Default)
The ADAS3023 offers two conversion modes to accommodate
varying applications, and both modes are set with the conversion
mode select bit, CMS (Bit 1) of the CFG register.
Setting CMS to 1 is useful for all applications where the full
500 kSPS sample rate of the device is not required. In this mode,
there is no maximum time restriction between conversions. This
mode is the default condition from the assertion of an asynchronous reset. The main difference between the normal mode and
warp mode is that the BUSY/SDO2 time, tCONV, is slightly longer
in normal mode than in warp mode.
Warp Mode (CMS = 0)
Setting CMS to 0 is useful where the full 2-channel throughput
of 500 kSPS is required. However, in this mode, the maximum
time between conversions is restricted. If this maximum period is
exceeded, the conversion result can be corrupted. Therefore, the
warp mode is best suited for continuously sampled applications.
Rev. A | Page 25 of 32
ADAS3023
Data Sheet
DIGITAL INTERFACE
The ADAS3023 digital interface consists of asynchronous
inputs and a 4-wire serial interface for conversion result
readback and configuration register programming.
the current configuration is applied to future conversions. This
pipeline ensures that the ADAS3023 has sufficient time to acquire
the next sample to the specified 16-bit accuracy.
This interface uses the three asynchronous signals (CNV, RESET,
and PD) and a 4-wire serial interface comprised of CS, SDO,
SCK, and DIN. CS can also be tied to CNV for some applications.
Register Pipeline
The CNV input initiates conversions for N enabled channels as
defined in the CFG register. The ADAS3023 is fully asynchronous
and can perform conversions at any frequency from dc up to
500 kSPS, depending on the settings specified in the configuration
register and the system serial clock rate.
The CFG register is written on the first 16 SCKs following the
EOC event, and it is updated on the next EOC event. To ensure
that all CFG updates are applied during a known safe instant to
the various circuit elements, the asynchronous data transfer is
synchronized to the ADAS3023 timing engine using the EOC
event. This synchronization introduces an inherent delay between
updating the CFG register setting and the application of the
configuration to a conversion. This pipeline, from the end of
the current conversion (n), consists of a one-deep delay before
the CFG setting takes effect. This means that two SOC and EOC
events must elapse before the setting (that is, the new channel,
gain, and so forth) takes effect. Note that the nomenclature (n),
(n + 1), and so forth is used in the remainder of the following
digital sections (Serial Data Interface, General Timing, and
Configuration Register) for simplicity. Note, however, that there
is no pipeline after the end of a conversion before data can be
read back.
CNV Rising—Start of Conversion (SOC)
RESET AND POWER-DOWN (PD) INPUTS
A rising edge on the CNV changes the state of the ADAS3023 from
track mode to hold mode, as well as all that is necessary to initiate a
conversion. All conversion clocks are generated internally. After a
conversion is initiated, the ADAS3023 ignores other activity on
the CNV line (governed by the throughput rate) until the end of
the conversion.
The asynchronous RESET and PD inputs can be used to reset
and power down the ADAS3023, respectively. Timing details
are shown in Figure 46.
CONVERSION CONTROL
Although CNV is a digital signal, take care to ensure fast, clean
edges with minimal overshoot, undershoot, and ringing. In
addition, avoid digital activity close to the sampling instant because
such activity can result in degraded SNR performance.
BUSY/SDO2 Falling Edge—End of Conversion (EOC)
The EOC is indicated by BUSY/SDO2 returning low and can be
used as a host interrupt. In addition, the EOC gates data access
to and from the ADAS3023. If the conversion result is not read
prior to the next EOC event, the data is lost. Furthermore, if the
CFG update is not completed prior to the EOC, it is discarded and
SEE NOTE
CNV
n–1
RESET/
PD
While the ADAS3023 is performing a conversion and the BUSY/
SDO2 output is driven high, the ADAS3023 uses a unique 2-phase
conversion process, allowing for safe data access and quiet time.
The CNV signal is decoupled from the CS pin, allowing multiple
ADAS3023 devices to be controlled by the same processor. For
applications where SNR is critical, the CNV source requires very
low jitter, which is achieved by using a dedicated oscillator or by
clocking CNV with a high frequency, low jitter clock. For applications where jitter is more tolerable or a single device is in use, tie
CNV to CS. For more information on sample clock jitter and
aperture delay, see the MT-007 Mini Tutorial, Aperture Time,
Aperture Jitter, Aperture Delay Time—Removing the Confusion.
tACQ
tRH
n
BUSY
CS
tCCS
n–2
SDO
CFG
tEN
tDIS
x
n+1
UNDEFINED
x
DEFAULT
x
x
SEE NOTE
NOTES
1. WHEN THE PART IS RELEASED FROM RESET, tACQ MUST BE
MET FOR CONVERSION n IF USING THE DEFAULT CFG
SETTING FOR CHANNEL IN0. WHEN THE PART IS RELEASED
FROM POWER-DOWN, tACQ IS NOT REQUIRED, AND THE FIRST
TWO CONVERSIONS, n AND n + 1, ARE UNDEFINED.
10942-017
Conversion results are presented to the serial data output pin
(SDO) after the end of a conversion. The 16-bit configuration
word, CFG, is programmed on the serial data input pin, DIN
during the first 16 SCKs of any data transfer. This CFG register
controls the settings, such as selecting the number of channels to
be converted, the programmable gain settings for each channel
group, and the reference choice (see Configuration Register
section for more information).
Figure 46. RESET and PD Timing
A rising edge on RESET or PD aborts the conversion process and
places SDO into high impedance, regardless of the CS level. Note
that RESET has a minimum pulse width (active high) time for
setting the ADAS3023 into the reset state. See the Configuration
Register section for the default CFG setting when the ADAS3023
returns from the reset state. If this default setting is used after
RESET is deasserted (Logic 0), for the conversion result to be
valid, a period equal to the acquisition time (tACQ) must elapse
before CNV can be asserted; otherwise, if a conversion is
initiated, the result is corrupted. In addition, the output data
from the previous conversion is cleared upon a reset; attempting
Rev. A | Page 26 of 32
Data Sheet
ADAS3023
to access the data result prior to initiating a new conversion
produces an invalid result.
interface uses the CS, SCK, SDO, and DIN signals. Timing signals
for a serial interface are shown in Figure 47.
Upon the device returning from power-down mode or from a reset
when the default CFG is not used, there is no tACQ requirement
because the first two conversions from power-up are undefined/
invalid because the one-deep delay pipeline requirement must
be satisfied to reconfigure the device to the desired setting.
SDO is activated when CS is asserted. The conversion result is
output on SDO and updated on the SCK falling edges. Simultaneously, the 16-bit CFG word is updated, if needed, on the serial
data input (DIN). The state of BUSY/SDO2 (Bit 0) determines the
output format of the MSB data when SDO is activated after the
EOC. Note that, in Figure 47, SCK is shown as idling high. SCK
can idle high or low, requiring the system developer to design an
interface that suits setup and hold times for both SDO and DIN.
SERIAL DATA INTERFACE
The ADAS3023 uses a simple 4-wire interface and is compatible
with FPGAs, DSPs, and common serial interfaces such as a
serial peripheral interface (SPI), QSPI™, and MICROWIRE®. The
tSCK
tSCKH
tSCKL
CS
tDIS
SCK
tSDOH
tEN
tSDOV
SDO
(MISO)
tDINS
tDINH
Figure 47. Serial Timing
Rev. A | Page 27 of 32
10942-018
DIN
(MOSI)
ADAS3023
Data Sheet
The converter busy signal is always output on the BUSY/SDO2
pin when CS is logic high. When the BUSY/SDO2 output is enabled when CS is brought low after the EOC, the SDO outputs the
data of Channel 0 to Channel 3 (CH0, CH1, CH2, and CH3), and
the SDO2 outputs the data of Channel 4 to Channel 7 (CH4, CH5,
CH6, and CH7) after 16 SCK rising edges, as shown in Figure 49.
The conversion result output on BUSY/SDO2 pin synchronizes to
the SCK falling edges. The conversion results are in twos complement format. Reading or writing data during the quiet conversion
phase (tCONV) may cause incorrect bit decisions.
GENERAL TIMING
Figure 48 and Figure 49 conversion timing diagrams show the
specific timing parameters, including the complete register to
conversion and readback pipeline delay. These figures detail the
timing from a power up or from returning from a full power
down by use of the PD input. When the BUSY/SDO2 output is
not enabled after the EOC, the data available on the SDO output
(MSB first) can be read after the16 SCK rising edges in sequential fashion (from Channel 0 (CH0) to Channel 7 (CH7)), as shown
in Figure 48.
SOC
SOC
SOC
tCYC
EOC
EOC
tCONV
POWER
UP
PHASE
NOTE 1
NOTE 2
CONVERSION (n)
ACQUISITION (n + 1)
NOTE 1
CONVERSION (n + 1)
ACQUISITION (n + 2)
CNV
tCNVH
NOTE 4
tAD
NOTE 3
CS
1
16
1
16
1
16
1
16 1
16
1
16
NOTE 2
SCK
DIN
CFG (n + 2)
SDO
CH0
BUSY/
SDO2
CFG (n + 3)
CH1
CH7
CH0
CH1
CH7
tCBD
10942-019
DATA (n)
DATA (n + 1)
NOTES
1. DATA ACCESS CAN ONLY OCCUR AFTER CONVERSION. BOTH CONVERSION RESULT AND THE CFG REGISTER ARE UPDATED AT THE END OF THE CONVERSION (EOC).
2. A TOTAL OF 16 SCK FALLING EDGES ARE REQUIRED FOR CONVERSION RESULT. AN ADDITIONAL 16 EDGES AFTER THE LAST CONVERSION RESULT ON BUSY READS BACK THE CFG ASSOCIATED
WITH CONVERSION.
3. CS CAN BE HELD LOW OR CONNECTED TO CNV. CS IS SHOWN WITH FULL INDEPENDENT CONTROL.
4. FOR OPTIMAL PERFORMANCE, DATA ACCESS SHOULD NOT OCCUR DURING THE SAMPLING INSTANT. A MINIMUM TIME OF AT LEAST THE APERATURE DELAY, tAD, SHOULD LAPSE PRIOR TO DATA ACCESS.
Figure 48. General Timing Diagram with BUSY/SDO2 Disabled
SOC
SOC
SOC
tCYC
EOC
tCONV
POWER
UP
PHASE
EOC
NOTE 1
NOTE 1
CONVERSION (n)
ACQUISITION (n + 1)
CONVERSION (n + 1)
ACQUISITION (n + 2)
CNV
tCNVH
NOTE 4
tAD
NOTE 3
1
16
1
16 1
16 1
16
1
16 1
16 1
16 1
16
NOTE 2
DIN
CFG (n + 2)
CFG (n + 3)
SDO
CH0
CH1
CH2
CH3
CH0
CH1
CH2
CH3
BUSY/
SDO2
CH4
CH5
CH6
CH7
CH4
CH5
CH6
CH7
DATA (n)
DATA (n + 1)
NOTES
1. DATA ACCESS CAN ONLY OCCUR AFTER CONVERSION. BOTH CONVERSION RESULT AND THE CFG REGISTER ARE UPDATED AT THE END OF THE CONVERSION (EOC).
2. A TOTAL OF 16 SCK FALLING EDGES ARE REQUIRED FOR CONVERSION RESULT. AN ADDITIONAL 16 EDGES AFTER THE LAST CONVERSION RESULT ON BUSY READS BACK THE CFG ASSOCIATED
WITH CONVERSION.
3. CS CAN BE HELD LOW OR CONNECTED TO CNV. CS IS SHOWN WITH FULL INDEPENDENT CONTROL.
4. FOR OPTIMAL PERFORMANCE, DATA ACCESS SHOULD NOT OCCUR DURING THE SAMPLING INSTANT. A MINIMUM TIME OF AT LEAST THE APERATURE DELAY, tAD, SHOULD LAPSE PRIOR TO DATA ACCESS.
Figure 49. General Timing Diagram with BUSY/SDO2 Enabled
Rev. A | Page 28 of 32
10942-020
CS
SCK
Data Sheet
ADAS3023
required for the user specified CFG to take effect. To ensure the
digital core is in the default state, apply an external reset after the
deassertion of PD. The default value is CFG[15:0] = 0xFFFF. To
read back the contents of the configuration register, CFG, an
additional 16 SCKs are provided after all of the channel data
have been read, and CFG is made available on the SDO output.
The default CFG settings configure the ADAS3023 as follows:
CONFIGURATION REGISTER
The configuration register, CFG, is a 16-bit programmable
register for selecting all of the user-programmable options of
the ADAS3023 (see Table 11).
The register is loaded when data is read back for the first
16 SCK rising edges, and it is updated at the next EOC. Note
that there is always a one-deep delay when writing to CFG, and
when reading back from CFG, it is the setting associated with
the current conversion.
•
•
•
•
•
•
The default CFG setting is applied when the ADAS3023 returns
from the reset state (RESET = high) to the operational state
(RESET = low). Returning from the full power-down state
(PD = high) to an enabled state (PD = low), the default CFG
setting is not applied and at least one dummy conversion is
Overwrites contents of the CFG register.
Selects the eight input channels mode.
Configures the PGIA gain to 0.20 (±20.48 V).
Enables the internal reference.
Selects normal conversion mode.
Disables the SDO2 readout mode.
Table 10. Configuration Register, CFG Bit Map; Default Value = 0xFFFF (1111 1111 1111 1111)
15
CFG
14
INx
13
INx
12
RSV
11
PGIA
10
PGIA
9
PGIA
8
PGIA
7
PGIA
6
PGIA
5
PGIA
4
PGIA
3
RSV
2
REFEN
1
CMS
0
BUSY/SDO2
Table 11. Configuration Register Description
Bit No.
15
Bit Name
CFG
[14:13]
INx
12
[11:4]
RSV
PGIA
[11:10]
[9:8]
[7:6]
[5:4]
3
2
PGIA
PGIA
PGIA
PGIA
RSV
REFEN
1
CMS
0
BUSY/SDO2
Description
Configuration update.
0 = keeps current configuration settings.
1 = overwrites contents of register.
Selection of the number of channels to be converted simultaneously.
Bit 14
Bit 13
Channels
0
0
2
0
1
4
1
0
6
1
1
8
Reserved. Setting or clearing this bit has no effect.
Programmable gain selection (see the Programmable Gain section).
Bit (Odd)
Bit (Even)
PGIA Gain
0
0
±10.24 V
0
1
±5.12 V
1
0
±2.56 V
1
1
±20.48 V (default)
Sets the gain of IN0.
Sets the gain of IN1.
Sets the gain of IN3 to IN2.
Sets the gain of IN4 to IN7.
Reserved. Setting or clearing this bit has no effect.
Internal reference (see the Pin Configuration and Function Descriptions and Voltage Reference Input/Output sections).
0 = disables the internal reference. Disable the internal reference buffer by pulling REFIN to ground.
1 = enables the internal reference (default).
Conversion mode selection (see the Conversion Modes section).
0 = uses the warp mode for conversions with a time between conversion restriction.
1 = uses the normal mode for conversions (default).
Secondary data output control using the BUSY/SDO2 pin.
0 = enables the device busy status when the CS pin is held high. On the CS falling edge, the MSB of Channel 1 is
presented on the BUSY/SDO2 input and subsequent data is presented on the SCK falling edges.
1 = enables the device busy status only (default). All data is transmitted via the SDO pin on the SCK falling edge.
Rev. A | Page 29 of 32
ADAS3023
Data Sheet
PACKAGING AND ORDERING INFORMATION
OUTLINE DIMENSIONS
0.30
0.25
0.18
31
30
0.50
BSC
TOP VIEW
1.00
0.95
0.85
0.45
0.40
0.35
1
21
11
20
PIN 1
INDICATOR
*4.70
4.60 SQ
4.50
EXPOSED
PAD
0.05 MAX
0.02 NOM
COPLANARITY
0.08
0.20 REF
SEATING
PLANE
40
10
BOTTOM VIEW
0.25 MIN
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
*COMPLIANT TO JEDEC STANDARDS MO-220-VJJD-5
WITH EXCEPTION TO EXPOSED PAD DIMENSION.
07-19-2012-B
PIN 1
INDICATOR
6.10
6.00 SQ
5.90
Figure 50. 40-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
6 mm × 6 mm Body, Very Thin Quad
(CP-40-15)
Dimensions shown in millimeters
ORDERING GUIDE
Model 1
ADAS3023BCPZ
ADAS3023BCPZ-RL7
EVAL-ADAS3023EDZ
1
Temperature Range
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
Package Description
40-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
40-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
Evaluation Board
Z = RoHS Compliant Part.
Rev. A | Page 30 of 32
Package Option
CP-40-15
CP-40-15
Data Sheet
ADAS3023
NOTES
Rev. A | Page 31 of 32
ADAS3023
Data Sheet
NOTES
©2013–2014 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D10942-0-2/14(A)
Rev. A | Page 32 of 32
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