DC209 - LTC1404CS8 Evaluation Kit Quick Start Guide

DEMO MANUAL DC209
HIGH SPEED A/D DEMO BOARD
LTC1404, SO-8 12-Bit 600ksps
A/D Converter Demo Board
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DESCRIPTIO
The LTC®1404 is a 1.6µs, 600ksps, sampling 12-bit A/D
converter that draws only 75mW from single 5V or ±5V
supplies. The LTC1404 demo board provides the user with
a way to evaluate the LTC1404 high speed A/D converter.
In addition, the LTC1404 demo board is intended to
illustrate the layout and bypassing techniques required to
obtain optimum performance from this part. The LTC1404
demo board is designed to be easy to use and requires only
±7V to ±15V supplies, a conversion-start signal and an
analog input signal. As shown in the Board Photo, the
LTC1404 is a very space efficient solution for
A/D users. By combining a 12-bit A/D, sample-and-hold,
reference and clock circuitry into a single SO package, all
the data acquisition circuitry, including the bypass caps,
can be placed into an area of only 0.19 inch2. The LTC1404
is intended for applications in telecommunications, digital
signal processing, imaging or any high speed, high resolution data acquisition application.
This manual shows how to use the demo board. Included
are timing diagrams, power supply requirements and
analog input range information. Additionally, a schematic,
parts list, drawings and dimensions of all the PC board
layers are included. An explanation of the layout and
bypass strategies used in this board is also included so
that anyone designing a PC board using the LTC1404 will
be able to get the maximum performance from the device.
Gerber files for this circuit board are available. Call the
LTC factory.
Some key features of this demo board include:
• Proven 600ksps 12-bit ADC surface mount layout
• Actual ADC footprint only 0.19 inch2, including
bypass capacitors
• 72dB SINAD and – 80dB THD at 100kHz inputs (Typ)
, LTC and LT are registered trademarks of Linear Technology Corporation.
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TYPICAL PERFORMANCE CHARACTERISTICS AND BOARD PHOTO
4096 Point FFT of LTC1404 Demo Board
Board Photo
0
fSAMPLE = 600kHz
fIN = 99.1699kHz
SINAD = 71dB
THD = –77dB
–10
–20
AMPLITUDE (dB)
–30
–40
–50
– 60
–70
–80
–90
–100
–110
–120
0
30 60 90 120 150 180 210 240 270 300
FREQUENCY (kHz)
1404 G05
DC209 BP
1
DEMO MANUAL DC209
HIGH SPEED A/D DEMO BOARD
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W
W
PACKAGE A D SCHE ATIC DIAGRA S
TOP VIEW
3
V+
4
J2
7V TO 15V
5
5D
6
7
J3
GND
10
2
9
AGND DGND
J4
–7V TO –15V
1
V–
CLK
INPUT
J1
BNC
A
QA
B
QB
C
QC
D
QD
ENP
RCO
VCC 1
8
VSS
AIN 2
7
CONV
VREF 3
6
CLK
GND 4
5
DOUT
LTC1404CS8
S8 PACKAGE
8-LEAD PLASTIC SO
14
DATA OUTPUT
13
12
11
U5C
74HC14
15
5
U5D
74HC14
R14
1k
6
ENT
CLK
U2
74HC595
CLR
12
14
10
11
11
U5E
74HC14
U5F
74HC14
R13
51Ω
DOUT
4
3
QA
SER
D0
2
D1
3
10
5D
D2
4
D3
5
D4
QG 6
QH 7
D5
QC
SRCLK
QD
SRCLR
QE
12
13
QF
RCLK
G
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
RDY
DOUT
REFRDY
D11
15
1
QB
13
RDY
U5B
74HC14
LOAD
U4
74HC161
CLK IN
8
9
C9
15pF
U5A
74HC14
1
2
1
3
5
7
9
11
13
15
17
D6
JP6
HEADER 9X2
DATA DISPLAY
D0
R1
1.2k
D0
D1
R2
1.2k
D1
D2
R3
1.2k
D2
D3
R4
1.2k
D3
D4
R5
1.2k
D4
D5
R6
1.2k
D5
D6
R7
1.2k
D6
D7
R8
1.2k
D7
D8
R9
1.2k
D8
D9
R10
1.2k
D9
D10
R11
1.2k
D10
D11
R12
1.2k
D11
QH* 9
14
–5A
5A
+
ANALOG
INPUT R17
100Ω
E1
BNC
+
C15
1000pF
C8
10µF
1
VSS
VCC
16V
2
AIN
CONV
3
CLK
VREF
C10 4 GND
DOUT
10µF
16V
U1
LTC1404CS8
NOTE 5
U7
LTC1175CS8-5
V
1
–
–5A
C11
0.1µF
2
3
4
5A
E2
5D
E3
C12
0.1µF
VIN
ILIM2
OUT
SENSE
VIN
ILIM4
SHDN
GND
8
7
1
JP7
2 3-PIN
3 HEADER
JP2
JP3 JP4
10
SRCLK
QC
SRCLR
QD
QE
12
7
13
6
RCLK
QF
G
QG
QH
5
QH*
1
JP5
4-PIN
3 SERIAL
I/O
4
HEADER
2
V+
U6
LT1121-5
1
VIN
OUT
TAB
4
GND
2
15
D7
1
D8
2
D9
3
D10
4
D11
5
REFRDY
6
5D
7
9
5D
C13
0.1µF
R16
10Ω
C5
47µF
16V
C6
0.1µF
4
U8
3 TC7SH04F
U3
74HC595
3
5
2
5A
+
NOTES: UNLESS OTHERWISE SPECIFIED
1. ALL RESISTANCES IN OHMS, 1/8W, 5%
2. ALL CAPACITANCES ARE 10%
3. ALL 74HCXXX CONNECTED TO 5D AND DGND
4. ALL LEDs PANASONIC LN1251C
5. DIGITAL AND ANALOG GND PLANES CONNECT AT PIN 4 ONLY
2
11
8
6
5
QA
QB
C7
10µF
16V
+
SER
2
4
6
8
10
12
14
16
18
+
C14
22µF
TANT
5A
R15
REFRDY 1.2k D12
5D
LED
NOTE 4
C1
0.1µF
U2 TO U5, U8
74HCXXX
C2
0.1µF
C3
0.1µF
C4
0.1µF
BYPASS CAPACITORS
C16
0.1µF
JP1
LED
ENABLE
DEMO MANUAL DC209
HIGH SPEED A/D DEMO BOARD
PARTS LIST
REFERENCE
DESIGNATOR
C1 to C4, C6, C11
to C13, C16
C5
C7, C8, C10
C9
C14
C15
D0 to D12
E1, J1
E2, E3
J2, J3, J4
JP1 to JP4
JP5
JP6
JP7
P2 to P4, P7
R1 to R12, R15
R13
R14
R16
R17
U1
U2, U3
U4
U5
U6
U7
U8
QUANTITY
9
1
3
1
1
1
13
2
2
3
4
1
1
1
4
13
1
1
1
1
1
2
1
1
1
1
1
PART NUMBER
12065C104KATM
DESCRIPTION
0.1µF 50V 10% X7R Capacitor
VENDOR
AVX
TELEPHONE
(843) 946-0362
TAJD476K016R
GRM235Y5V106Z016
12065C150KATM
TAJB226K06R
12065A102KATM
LN1251C-(TR)
222420-1
2501-02
575-4
3801S-2-G1
3801S-4-G1
3201S-18-G1
3801S-3-G1
CCIJ230-G
CR18-122JM
CR18-510JM
CR18-102JM
CR18-100JM
CR18-101JM
LTC1404CS8
MC74HC595AD
MC74HC161AD
MC74HC14AD
LT1121-5
LTC1175CS8-5
TC7SH04F
47µF 16V 10% Tantalum Capacitor
10µF 16V 10% Ceramic Capacitor
15pF 50V 10% X7R Capacitor
22µF 6.3V 10% Tantalum Capacitor
1000pF 50V 10% NPO Chip Capacitor
45mW 2.1V Red Surface Mount LED
50Ω PC-Mount BNC Vert Connector
0.094 Noninsulating Terminal
0.175-ID Banana Jack
2-Pin Header
4-Pin Header
2-Row 18-Pin Header
3-Pin Header
Shunt
1.2k 1.8W 5% Chip Resistor
51Ω 1/8W 5% Chip Resistor
1k 1/8W 5% Chip Resistor
10Ω 1/8W 5% Chip Resistor
100Ω 1/8W 5% Chip Resistor
12-Bit High Speed A/D Converter
8-Bit Shift Register IC
4-Bit Binary Counter IC
Hex Inverter IC
5V Regulator IC
– 5V Regulator IC
Inverter IC
AVX
Murata Elect.
AVX
AVX
AVX
Panasonic
AMP
Mill-Max
Keystone
Comm Con
Comm Con
Comm Con
Comm Con
Comm Con
TAD
TAD
TAD
TAD
TAD
LTC
Motorola
Motorola
Motorola
LTC
LTC
Toshiba
(207) 282-5111
(814) 237-1431
(843) 946-0362
(207) 282-5111
(843) 946-0362
(201) 348-5217
(717) 564-0100
(516) 922-6000
(718) 956-8900
(626) 301-4200
(626) 301-4200
(626) 301-4200
(626) 301-4200
(626) 301-4200
(800) 508-1521
(800) 508-1521
(800) 508-1521
(800) 508-1521
(800) 508-1521
(408) 432-1900
(800) 441-2447
(800) 441-2447
(800) 441-2447
(408) 432-1900
(408) 432-1900
(714) 455-2000
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OPERATIO
OPERATING THE BOARD
Powering the Board
The Analog Input
To use the demo board, apply 7V to 15V to banana jack J2,
–7V to –15V to jack J4 and 0V (ground) to J3. Make sure
that the power source(s) for these voltages can supply at
least 200mA. Be careful to observe the correct polarity.
Onboard regulators provide ±5V to the LTC1404. An
LT1121-5 regulator provides 5V for analog and digital
circuitry and – 5V is provided for the A/D and buffer by the
LTC1175-5 regulator. A jumper (JP7) allows the ADC to be
evaluated with a single 5V supply, if desired.
Analog signals are applied to the LTC1404 demo board
using BNC connector E1. The analog signal input range is
±2.5V. Optimum performance is achieved using a signal
source that has low output impedance, low noise and low
distortion. Signal generators, such as the B&K Type 1051
Sine Generator, give excellent results. Further, this generator can be configured to operate referenced to a master
clock signal, as shown in Figure 1. If this or other low noise
3
DEMO MANUAL DC209
HIGH SPEED A/D DEMO BOARD
U
OPERATIO
REFERENCE
FREQUENCY
IN
BRUEL & KJAER
TYPE 1051 SINE
GENERATOR
VOUT
E1
ANALOG
INPUT
LTC1404
12-BIT A/D
DEMO BOARD
HEWLETT PACKARD
HP3326A
REFERENCE
GENERATOR
FREQUENCY
OUT
JP6
1-12
DOUT
is driven by the clock signal applied to CLK input J1. The
CONV signal remains low, as shown in Figure 2, until the
conversion is completed. During a conversion, transition
of the CONV input can result in errors in the conversion
value.
HEWLETT PACKARD
HP1663A
LOGIC
ANALYZER
Reading the Output Data
CLOCK
CLK
J1
The ADC serial data output is converted to parallel and
buffered by the two 74HC595 shift registers and is available on connector JP6. The shift registers are used to drive
the LEDs and connector JP6. In a practical circuit, the
serial data of the ADC can be read directly. Serial data is
available at jumper JP5. The ADC’s serial I/O can be driven
directly at JP5 by removing jumpers JP2, JP3 and JP4.
DC209 F01
Figure 1. Typical Setup for LTC1404 Demo Board
generators are not available, the LTC1404 demo board has
an RC lowpass filter, R17/C15, that reduces signal source
noise. This filter is also beneficial when an input signal’s
bandwidth is less than one-half the sampling frequency.
The filter reduces out-of-band noise that could compromise the LTC1404’s conversion performance.
The LTC1404 output data is in two’s complement format.
The data can be converted to offset binary by using D11
(JP6, Pin 17) instead of D11. Offset binary is used when an
FFT is to be performed on the sampled data. A data ready
(RDY) line (JP6, Pin 13) is provided to latch the DOUT
word. DOUT is valid on the rising edge of Data Ready. Two
ground lines are provided on the connector (JP6, Pins 16
and 18) for grounding a receiving system to the board.
The filter is not necessary when the LTC1404 is used in
undersampling applications, such as recovering a 50kHz
baseband signal modulating a 455kHz carrier. Its wide
5MHz input bandwidth easily allows the LTC1404 to
undersample the 455kHz carrier. The 50kHz signal can be
recovered from the resultant conversion results.
The LTC1404 DOUT word can be acquired with a logic
analyzer. Conversion data can be stored on a disk and
easily transferred to a PC by using a logic analyzer that has
a PC-compatible floppy drive (such as an HP1663A). Once
the data is transferred to a PC, programs such as MathCAD
Applying the Conversion-Start Signal
A conversion is initiated by a rising edge on the LTC1404
CONV input pin. This control signal is generated by U4 and
t2
t7
t3
1
2
3
4
5
6
7
8
9
10
11
12
13
15
14
16
1
2
CLK
t4
t5
CONV
t6
INTERNAL
S/H STATUS
tACQ
SAMPLE
HOLD
SAMPLE
HOLD
t8
DOUT
Hi-Z
REFRDY
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Hi-Z
REFRDY
REFRDY BIT + 12-BIT DATA WORD
tCONV
tSAMPLE
Figure 2. ADC Digital Timing Diagram (Timing Specifications Are Found in the LTC1404 Data Sheet)
4
DC209 F02
DEMO MANUAL DC209
HIGH SPEED A/D DEMO BOARD
U
OPERATIO
or Excel can be used to calculate FFTs. The FFTs can be
used to obtain LTC1404 AC specifications, such as signalto-noise ratio and total harmonic distortion.
LEDs D0 to D11 provide a visual display of the LTC1404
digital output word. D0 is the LSB and D11 is the MSB.
Jumper JP1 can be removed to disable the LEDs, reducing
supply consumption by up to 36mA.
LAYOUT
opens a portion of the ground plane may reduce the
ground plane’s efficiency, the ground plane’s solder side
has a limited number of plane-breaking traces within it.
The analog and digital traces do not cross each other
(whether on the board’s top or bottom side) or run
adjacent to each other. The LTC1404’s ground pin (GND)
is connected directly to the analog ground plane. This
produces the lowest noise condition.
BYPASS
The use of separate analog and digital ground planes is a
good practice for a well designed PC board using the
LTC1404. The proper way to make the analog and digital
ground planes can be seen by examining the solder side of
the PCB layout. The two ground planes are completely
isolated except for one connection near the top of the
board. The two ground planes follow the same path on the
component and solder sides of the board to reduce coupling between the ground planes. Because any trace that
It is important that the supply and reference bypass
capacitors for the LTC1404 be placed as close as possible
to the supply and reference pins. The ground side of the
capacitors should have very short paths to analog ground.
The VCC and VREF pins should be bypassed with high
quality (low ESR) tantalum capacitors of at least 10µF. VSS
is less critical and should be bypassed with a ceramic
capacitor of at least 0.1µF.
Table 1
JUMPER
JUMPER NAME
JUMPER CONNECTION
JP1
LED Enable
JP2
CONV
(CS on Silkscreen)
Shorted for normal operation. If open, the CONV line can be driven externally
to control the start of conversion
JP3
DOUT
Shorted for normal operation. If open, the DOUT serial data output line can be
read externally
JP4
CLK
Shorted for normal operation. If open, the CLK line can be driven externally
Shorted to enable LEDs. Open to disable the LEDs
Table 2
INPUT/OUTPUT PIN
E1
J1
J2
J3
J4
JP6-1
JP6-2
JP6-3
JP6-4
JP6-5
JP6-6
FUNCTION
Analog Input: 0V to 4.096V, Unipolor or
±2.048V Bipolar
Serial Clock Input: 0.1MHz to 9.6MHz
7V to 15V at 200mA
Ground
–7V to –15V at 100mA
DOUT0 (LSB)
DOUT1
DOUT2
DOUT3
DOUT4
DOUT5
INPUT/OUTPUT PIN
FUNCTION
JP6-7
DOUT6
JP6-8
DOUT7
JP6-9
DOUT8
JP6-10
DOUT9
JP6-11
DOUT10
JP6-12
DOUT11 (MSB)
JP6-13
RDY*
JP6-14
DOUT (Serial Data)
JP6-15
REFRDY (Logic High = Stable Reference)
JP6-16
Digital GND
JP6-17
Inverted DOUT11
JP6-18
Digital GND
* Can be used by an external system to latch the ADC’s output. Latch data
on the rising edge.
5
DEMO MANUAL DC209
HIGH SPEED A/D DEMO BOARD
U
W
PCB LAYOUT A D FIL
Component Side Silkscreen
Component Side
Component Side Solder Mask
6
DEMO MANUAL DC209
HIGH SPEED A/D DEMO BOARD
U
W
PCB LAYOUT A D FIL
Solder Side Solder Mask
Solder Side
Pastemask Top
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
7
DEMO MANUAL DC209
HIGH SPEED A/D DEMO BOARD
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PC FAB DRAWI G
3.650
F F
D
H
C
I
I
B
I
A
A
I
A
H
H
I
I
I
I
C
I
3.000
E
C
I
F F F
H
C
B
I
H
I
C
H
I
H
I
I
C
C
I
C
I
E
C
G
B
C
F
I
F
F
F
F
B
D
DC209 FD
NOTES:
1. MATERIAL: FR4 2 OZ COPPER CLAD THICKNESS
0.062 ±0.006 TOTAL OF 2 LAYERS
2. FINISH:
ALL PLATED HOLES 0.001 MIN/0.0015 MAX
COPPER PLATE ELECTRODEPOSITED TIN-LEAD
COMPOSITION BEFORE REFLOW, SOLDER
MASK OVER BARE COPPER (SMOBC)
3. SOLDER MASK: BOTH SIDES USING GREEN SR1020 OR EQUIVALENT
4. SILKSCREEN: USING WHITE NONCONDUCTIVE EPOXY INK
5. ALL DIMENSIONS ARE IN INCHES
8
Linear Technology Corporation
SYMBOL DIAMETER
NUMBER
OF HOLES
PLATED
A
0.207
3
YES
B
0.125
4
YES
C
0.095
10
YES
D
0.072
2
NO
E
0.052
2
YES
F
0.040
33
YES
G
0.032
130
YES
H
0.025
15
YES
I
0.020
56
YES
dc209f LT/TP 0599 500 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com
 LINEAR TECHNOLOGY CORPORATION 1999