Programmable Frequency Sweep and Output Burst Waveform Generator AD5930 Data Sheet

Programmable Frequency Sweep and Output Burst Waveform Generator AD5930 Data Sheet
Programmable Frequency Sweep and
Output Burst Waveform Generator
AD5930
Data Sheet
FEATURES
GENERAL DESCRIPTION
Programmable frequency profile
No external components necessary
Output frequency up to 25 MHz
Burst and listen capability
Preprogrammable frequency profile minimizes number of
DSP/µcontroller writes
Sinusoidal/triangular/square wave outputs
Automatic or single pin control of frequency stepping
Waveform starts at known phase
Increments at 0° phase or phase continuously
Power-down mode: 20 µA
Power supply: 2.3 V to 5.5 V
Automotive temperature range: −40°C to +125°C
20-lead pb-free TSSOP
The AD59301 is a waveform generator with programmable
frequency sweep and output burst capability. Utilizing
embedded digital processing that allows enhanced frequency
control, the device generates synthesized analog or digital
frequency-stepped waveforms. Because frequency profiles
are preprogrammed, continuous write cycles are eliminated
and thereby free up valuable DSP/µcontroller resources.
Waveforms start from a known phase and are incremented
phase continuously, which allows phase shifts to be easily
determined. Consuming only 8 mA, the AD5930 provides a
convenient low power solution to waveform generation.
The AD5930 can be operated in a variety of modes. In
continuous output mode, the device outputs the required
frequency for a defined length of time and then steps to the
next frequency. The length of time the device outputs a
particular frequency is either preprogrammed and the device
increments the frequency automatically, or, alternatively, is
incremented externally via the CTRL pin. In burst mode, the
device outputs its frequency for a length of time and then
returns to midscale for a further predefined length of time
before stepping to the next frequency. When the MSBOUT pin
is enabled, a digital output is generated.
APPLICATIONS
Frequency sweeping/radar
Network/impedance measurements
Incremental frequency stimulus
Sensory applications
Proximity and motion
BFSK
Frequency bursting/pulse trains
(continued on Page 3)
FUNCTIONAL BLOCK DIAGRAM
DVDD
STANDBY
AD5930
CAP/2.5V
DGND
AGND AVDD
REGULATOR
VCC
2.5V
MCLK
SYNC
SYNCOUT
BUFFER
OUTPUT BURST
CONTROLLER
DATA
DGND O/P
SYNC
BUFFER
INCREMENT
CONTROLLER
DATA
INCR
CTRL
FREQUENCY
CONTROLLER
DATA
24-BIT
PIPELINED
DDS CORE
MSBOUT
10-BIT
DAC
IOUTB
IOUT
24
AND CONTROL
SERIAL INTERFACE
FSYNC SCLK
CONTROL
REGISTER
ON-BOARD
REFERENCE
FULL-SCALE
CONTROL
REF
SDATA
FSADJUST
COMP
05333-001
INTERRUPT
Figure 1.
1
Protected by US Patent Number 6747583.
Rev. C
Document Feedback
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 ©2005–2015 Analog Devices, Inc. All rights reserved.
Technical Support
www.analog.com
AD5930
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Serial Interface ............................................................................ 17
Applications ....................................................................................... 1
Powering up the AD5930 .......................................................... 17
General Description ......................................................................... 1
Programming the AD5930........................................................ 17
Functional Block Diagram .............................................................. 1
Setting up the Frequency Sweep............................................... 19
Revision History ............................................................................... 2
Activating and Controlling the Sweep..................................... 20
General Description ......................................................................... 3
Outputs from the AD5930 ........................................................ 21
Specifications..................................................................................... 4
Applications Information .............................................................. 22
Timing Characteristics..................................................................... 6
Grounding and Layout .............................................................. 22
Absolute Maximum Ratings............................................................ 8
AD5930 to ADSP-21467 Interface ........................................... 22
ESD Caution .................................................................................. 8
AD5930 to 68HC11/68L11 Interface ....................................... 23
Pin Configuration and Function Descriptions ............................. 9
AD5930 to 80C51/80L51 Interface .......................................... 23
Typical Performance Characteristics ........................................... 11
AD5930 to DSP56002 Interface ............................................... 23
Terminology .................................................................................... 15
Evaluation Board ........................................................................ 24
Theory of Operation ...................................................................... 16
Schematic..................................................................................... 25
The Frequency Profile................................................................ 16
Outline Dimensions ....................................................................... 27
Output Modes ............................................................................. 16
Ordering Guide .......................................................................... 27
REVISION HISTORY
7/15—Rev. B to Rev. C
Change to Figure 6 and Figure 7..................................................... 7
Change to Table 4 ............................................................................. 9
Changed Applications Section to Applications Information
Section and Changed ADSP-2101 to ADSP-21467.................... 22
7/12—Rev. A to Rev. B
Change to Ordering Guide ............................................................ 27
2/12—Rev. 0 to Rev. A
Change to Figure 2 ........................................................................... 5
Changes to Figure 22, Figure 23, Figure 24, Figure 25,
and Figure 26 ................................................................................... 13
Changes to Figure 27, Figure 28, Figure 29, and
Figure 30 .......................................................................................... 25
11/05—Revision 0: Initial Version
Rev. C | Page 2 of 28
Data Sheet
AD5930
GENERAL DESCRIPTION
(continued from Page 1)
To program the device, the user enters the start frequency, the
increment step size, the number of increments to be made, and
the time interval that the part outputs each frequency. The
frequency sweep profile is initiated, started, and executed by
toggling the CTRL pin.
A number of different sweep profiles are offered. Frequencies can
be stepped in triangular-sweep mode, which continuously sweeps
up and down through the frequency range. Alternatively, in sawsweep mode, the frequency is swept up through the frequency
range, but returns to the initial frequency before executing the
sweep again. In addition, a single frequency or burst can be
generated without any sweep.
The AD5930 is written to via a 3-wire serial interface, which
operates at clock rates up to 40 MHz. The device operates with
a power supply from 2.3 V to 5.5 V. Note that AVDD and DVDD
are independent of each other and can be operated from
different voltages. The AD5930 also has a standby function,
which allows sections of the device that are not being used
to be powered down.
The AD5930 is available in a 20-lead pb-free TSSOP package.
Rev. C | Page 3 of 28
AD5930
Data Sheet
SPECIFICATIONS
AVDD = DVDD = 2.3 V to 5.5 V, AGND = DGND = 0 V, TA = TMIN to TMAX, RSET = 6.8 kΩ, RLOAD = 200 Ω for IOUT and IOUTB,
unless otherwise noted.
Table 1.
Parameter
SIGNAL DAC SPECIFICATIONS
Resolution
Update Rate
IOUT Full-Scale2
VOUT Peak-to-Peak
VOUT Offset
VMIDSCALE
Output Compliance
DC Accuracy
Integral Nonlinearity (INL)
Differential Nonlinearity (DNL)
DDS SPECIFICATIONS
Dynamic Specifications
Signal-to-Noise Ratio
Total Harmonic Distortion
Spurious-Free Dynamic Range
(SFDR)
Wideband (0 to Nyquist)
Narrowband (±200 kHz)
Clock Feedthrough
Wake-Up Time
OUTPUT BUFFER
VOUT Peak-to-Peak
Output Rise/Fall Time2
VOLTAGE REFERENCE
Internal Reference
External Reference Range
REFOUT Input Impedance
Reference TC2
LOGIC INPUTS
Input Current
VINH, Input High Voltage
Min
Y Grade1
Typ
10
3
0.56
45
0.325
50
4.0
0.8
±1.5
±0.75
53
60
−60
−62
−76
−50
1.7
0
1.15
1.18
Bits
MSPS
mA
V
mV
V
V
From 0 V to the trough of the waveform
Voltage at midscale output
AVDD = 2.3 V, internal reference used3
fMCLK = 50 MHz, fOUT = fMCLK/4096
fMCLK = 50 MHz, fOUT = fMCLK/4096
−52
−73
dBc
dBc
dBc
ms
fMCLK = 50 MHz, fOUT = fMCLK/50
fMCLK = 50 MHz, fOUT = fMCLK/50
Up to 16 MHz out
From standby
DVDD
V
ns
Typically, square wave on MSBOUT and SYNCOUT
1.26
1.3
V
V
kΩ
kΩ
ppm/°C
±1
1.7
2.0
2.8
0.6
0.7
0.8
3
DVDD − 0.4 V
0.4
5
Test Conditions/Comments
dB
dBc
−53
1
25
90
0.1
Unit
LSB
LSB
12
VINL, Input Low Voltage
CIN, Input Capacitance2
LOGIC OUTPUTS2
VOH, Output High Voltage
VOL, Output Low Voltage
Floating-State O/P Capacitance
Max
µA
V
V
V
V
V
V
pF
V
V
pF
Rev. C | Page 4 of 28
VIN @ REF pin < Internal VREF
VIN @ REF pin > Internal VREF
DVDD = 2.3 V to 2.7 V
DVDD = 2.7 V to 3.6 V
DVDD = 4.5 V to 5.5 V
DVDD = 2.3 V to 2.7 V
DVDD = 2.7 V to 3.6 V
DVDD = 4.5 V to 5.5 V
ISINK = 1 mA
ISINK = 1 mA
Data Sheet
Parameter
POWER REQUIREMENTS
AVDD/DVDD
IAA
IDD
IAA + IDD
Low Power Sleep Mode
AD5930
Min
Y Grade1
Typ
Max
Unit
3.8
2.4
6.2
5.5
4
2.7
6.7
V
mA
mA
mA
20
140
85
240
µA
µA
2.3
Test Conditions/Comments
fMCLK = 50 MHz, fOUT = fMCLK/7
Device is reset before putting into standby
All outputs powered down, MCLK = 0 V, serial interface active
All outputs powered down, MCLK active, serial interface active
Operating temperature range is as follows: Y Version: −40°C to +125°C; typical specifications are at 25°C.
Guaranteed by design.
3
Minimum RSET = 3.9 kΩ.
1
2
RSET
6.8V
10nF
CAP/2.5V
REGULATOR
AD5930
12
REFOUT
ON-BOARD
REFERENCE
SIN
ROM
FSADJUST
FULL-SCALE COMP
CONTROL
10-BIT
DAC
AVDD
10nF
IOUT
RLOAD
200Ω
Figure 2. Test Circuit Used to Test the Specifications
Rev. C | Page 5 of 28
20pF
05333-002
100nF
AD5930
Data Sheet
TIMING CHARACTERISTICS
All input signals are specified with tr = tf = 5 ns (10% to 90% of VDD) and timed from a voltage level of (VIL + VIH)/2.
See Figure 4 to Figure 7. DVDD = 2.3 V to 5.5 V, AGND = DGND = 0 V, all specifications TMIN to TMAX, unless otherwise noted.
Table 2.1
Parameter
t1
t2
t3
t4
t5
t6
t7
t8
t9
t10
t11
t12
t13
t14
t15
t16
t17
Unit
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns typ
ns typ
ns typ
ns typ
ns typ
ns max
Conditions/Comments
MCLK period
MCLK high duration
MCLK low duration
SCLK period
SCLK high time
SCLK low time
FSYNC to SCLK falling edge setup time
FSYNC to SCLK hold time
Data setup time
Data hold time
Minimum CTRL pulse width
CTRL rising edge to MCLK falling edge setup time
CTRL rising edge to IOUT/IOUTB delay (initial pulse, includes initialization)
CTRL rising edge to IOUT/IOUTB delay (initial pulse, includes initialization)
Frequency change to SYNC output, saw sweep, each frequency increment
Frequency change to SYNC output, saw sweep, end of sweep
Frequency change to SYNC output, triangle sweep, end of sweep
MCLK falling edge after 16th clock edge to MSB out
Guaranteed by design, not production tested.
t1
MCLK
05333-003
t2
t3
Figure 3. Master Clock
t5
t4
SCLK
t7
t6
t8
FSYNC
t10
t9
SDATA
D15
D14
D2
D1
Figure 4. Serial Timing
Rev. C | Page 6 of 28
D0
D15
D14
05333-004
1
Limit at TMIN, TMAX
20
8
8
25
10
10
5
10
5
3
2 x t1
0
10 x t1
8 x t1
2 x t1
2 x t1
2 x t1
20
Data Sheet
AD5930
t12
MCLK
CTRL
05333-005
t11
IOUT/IOUTB
t13
Figure 5. CTRL Timing
CTRL
t13
IOUT
SYNC O/P
(Each Frequency
Increment)
SYNC O/P
(End of Sweep)
05333-006
t14
t15
Figure 6. CTRL Timing, Saw-Sweep Mode
CTRL
t13
IOUT
SYNC O/P
(End of Sweep)
t14
t16
Figure 7. CTRL Timing, Triangular-Sweep Mode
Rev. C | Page 7 of 28
05333-007
SYNC O/P
(Each Frequency
Increment)
AD5930
Data Sheet
ABSOLUTE MAXIMUM RATINGS
TA = 25°C, unless otherwise noted.
Table 3.
Parameter
AVDD to AGND
DVDD to DGND
AGND to DGND
CAP/2.5V to DGND
Digital I/O Voltage to DGND
Analog I/O Voltage to AGND
Operating Temperature Range
Automotive (Y Version)
Storage Temperature Range
Maximum Junction Temperature
TSSOP Package (4-Layer Board)
θJA Thermal Impedance
θJC Thermal Impedance
Reflow Soldering (Pb-Free)
Peak Temperature
Time at Peak Temperature
Rating
−0.3 V to +6.0 V
−0.3 V to +6.0 V
−0.3 V to +0.3 V
−0.3 V to 2.75 V
−0.3 V to DVDD + 0.3 V
−0.3 V to AVDD + 0.3 V
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
ESD CAUTION
−40°C to +125°C
−65°C to +150°C
+150°C
112°C/W
27.6°C/W
300°C
260(+0/−5)°C
10 sec to 40 sec
Rev. C | Page 8 of 28
Data Sheet
AD5930
FSADJUST
1
20
IOUTB
REF 2
19
IOUT
COMP 3
18
AGND
AVDD 4
DVDD
5
CAP/2.5V
AD5930
TOP VIEW
(Not to Scale)
17
STANDBY
16
FSYNC
SCLK
6
15
DGND 7
14
SDATA
MCLK 8
13
CTRL
9
12
INTERRUPT
MSBOUT 10
11
DGND O/P
SYNCOUT
05333-008
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Figure 8. Pin Configuration
Table 4. Pin Function Descriptions
Pin No.
1
Mnemonic
FSADJUST
2
REF
3
4
COMP
AVDD
5
DVDD
6
CAP/2.5V
7
8
DGND
MCLK
9
SYNCOUT
10
MSBOUT
11
12
DGND O/P
INTERRUPT
13
CTRL
14
SDATA
15
16
SCLK
FSYNC
17
STANDBY
Description
Full-Scale Adjust Control. A resistor (RSET) must be connected externally between this pin and AGND.
This determines the magnitude of the full-scale DAC current. The relationship between RSET and the
full-scale current is:
IOUTFULL-SCALE = 18 × VREFOUT/RSET
where VREFOUT = 1.20 V nominal and RSET = 6.8 kΩ typical.
Voltage Reference. This pin can be an input or an output. The AD5930 has an internal 1.18 V reference, which
is made available at this pin. Alternatively, this reference can be overdriven by an external reference, with a
voltage range as given in the Specifications section. A 10 nF decoupling capacitor should be connected
between REF and AGND.
DAC Bias Pin. This pin is used for decoupling the DAC bias voltage to AVDD.
Positive Power Supply for the Analog Section. AVDD can have a value from +2.3 V to +5.5 V. A 0.1 µF decoupling
capacitor should be connected between AVDD and AGND.
Positive Power Supply for the Digital Section. DVDD can have a value from +2.3 V to +5.5 V. A 0.1 µF decoupling
capacitor should be connected between DVDD and DGND.
Digital Circuitry. Operates from a 2.5 V power supply. This 2.5 V is generated from DVDD using an on-board
regulator. The regulator requires a decoupling capacitor of typically 100 nF, which is connected from CAP/2.5V
to DGND. If DVDD is equal to or less than 2.7 V, CAP/2.5V can be shorted to DVDD.
Ground for all Digital Circuitry. This excludes digital output buffers.
Digital Clock Input. DDS output frequencies are expressed as a binary fraction of the frequency of MCLK.
The output frequency accuracy and phase noise are determined by this clock.
Digital Output for Sweep Status Information. User selectable for end of sweep (EOS) or frequency increments
through the control register (SYNCOP bit). This pin must be enabled by setting Control Register Bit SYNCOPEN to 1.
Digital Output. The inverted MSB of the DAC data is available at this pin. This output pin must be enabled by
setting bit MSBOUTEN in the control register to 1.
Separate DGND Connection for Digital Output Buffers. Connect to DGND.
Digital Input. This pins acts as an interrupt during a frequency sweep. A low to high transition is sampled by the
internal MCLK, which resets internal state machines. This results in the DAC output going to midscale.
Digital Input. Triple function pin for initialization, start, and external frequency increments. A low-to-high transition,
sampled by the internal MCLK, is used to initialize and start internal state machines, which then execute the preprogrammed frequency sweep sequence. When in auto-increment mode, a single pulse executes the entire sweep
sequence. When in external increment mode, each frequency increment is triggered by a pulse.
Serial Data Input. The 16-bit serial data-word is applied to this input with the register address first followed by the
MSB to LSB of the data.
Serial Clock Input. Data is clocked into the AD5930 on each falling SCLK edge.
Active Low Control Input. This is the frame synchronization signal for the serial data. When FSYNC is taken low,
the internal logic is informed that a new word is being loaded into the device.
Active High Digital Input. When this pin is high, the internal MCLK is disabled, and the reference DAC and regulator
are powered down. For optimum power saving, it is recommended to reset the AD5930 before putting it into
standby, as this results in a shutdown current of typically 20 µA.
Rev. C | Page 9 of 28
AD5930
Pin No.
18
19
Mnemonic
AGND
IOUT
20
IOUTB
Data Sheet
Description
Ground for all Analog Circuitry.
Current Output. This is a high impedance current source output. A load resistor of nominally 200 Ω should be
connected between IOUT and AGND. A 20 pF capacitor to AGND is also recommended to act as a low-pass filter
and to reduce clock feedthrough. In conjunction with IOUTB, a differential signal is available.
Current Output. IOUTB is the compliment of IOUT. This pin should preferably be tied through an external load
resistor of 200 Ω to AGND, but can be tied directly to AGND. A 20 pF capacitor to AGND is also recommended as a
low-pass filter to reduce clock feedthrough. In conjunction with IOUT, a differential signal is available.
Rev. C | Page 10 of 28
Data Sheet
AD5930
TYPICAL PERFORMANCE CHARACTERISTICS
–40
9
TA = 25°C
AVDD = 5V
MSBOUT, SYNCOUT ENABLED
8
–50
DVDD = 5V
7
SFDR (dBc)
DVDD = 3V
4
–60
FOUT = MCLK/50
–65
–70
DVDD = 5V, FOUT = MCLK/7
3
–75
2
FOUT = MCLK/3
0
5
10
15
20
25
30
35
40
45
05333-027
DVDD = 3V, FOUT = MCLK/7
1
05333-030
–80
–85
–90
50
0
5
10
MCLK FREQUENCY (MHz)
20
25
30
35
40
45
50
MCLK FREQUENCY (MHz)
Figure 9. Current Consumption (IDD) vs. MCLK Frequency
Figure 12. Wideband SFDR vs. MCLK Frequency
7
–60
TA = 25°C
MCLK = 50MHz
AVDD = DVDD = 3V/5V
MCLK = 50MHz
CREG = 0111 1111 1111
TA = 25°C
MSBOUT ON,
SYNCOUT ON
6
–65
MSBOUT OFF,
SYNCOUT ON
3
MSBOUT OFF,
SYNCOUT OFF
2
FOUT = MCLK/50
–70
MSBOUT ON,
SYNCOUT OFF
4
SFDR (dBc)
5
IDD (mA)
15
FOUT = MCLK/3
–75
–80
–85
05333-028
1
–90
1kHz
100kHz
1MHz
5MHz
15MHz
25MHz
500kHz
10kHz
500kHz
2MHz
10MHz
20MHz
FOUT = MCLK/7
0
5
10
15
20
25
30
35
40
45
05333-031
IDD (mA)
5
0
FOUT = MCLK/7
–55
6
0
AVDD = DVDD = 3V/5V
MCLK = 50MHz
CREG = 0111 1111 1111
TA = 25°C
–45
50
MCLK FREQUENCY (MHz)
FOUT (Hz)
Figure 10. IDD vs. FOUT for Various Digital Output Conditions
Figure 13. Narrowband SFDR vs. MCLK Frequency
–30
3.5
AIDD
3.0
–40
AVDD = DVDD = 3V/5V
CREG = 0111 1111 1111
TA = 25°C
MCLK = 50MHz
2.5
–50
SFDR (dBc)
1.5
–60
MCLK = 10MHz
–70
1.0
1
2
3
MCLK = 30MHz
–80
4
–90
0.001
05333-032
0.5
0
MCLK = 1MHz
LEGEND
1. SINEWAVE OUTPUT, INTERNALLY CONTROLLED SWEEP
2. TRIANGULAR OUTPUT, INTERNALLY CONTROLLED SWEEP
3. SINEWAVE OUTPUT, EXTERNALLY CONTROLLED SWEEP
4. TRIANGULAR OUTPUT, EXTERNALLY CONTROLLED SWEEP
05333-029
IDD (mA)
DIDD
2.0
0.01
0.1
1
10
100
FOUT (MHz)
CONTROL OPTION (See Legend)
Figure 11. IDD vs. Output Waveform Type and Control
Figure 14. Wideband SFDR vs. FOUT for Various MCLK Frequencies
Rev. C | Page 11 of 28
AD5930
Data Sheet
70
12
TA = 25°C
AVDD = DVDD = 5V
fOUT = FMCLK/4096
10
NUMBER OF DEVICES
65
55
50
45
6
4
2
05333-034
40
8
0
10M
20M
30M
40M
05333-025
SNR (dB)
60
0
552
50M
554
556
558
MCLK FREQUENCY (MHz)
560
562
564
566
568
570
572
46.0
46.2
VOUT PEAK-TO-PEAK (mV)
Figure 15. SNR vs. MCLK Frequency
Figure 18. Histogram of VOUT Peak-to-Peak
12
1.25
AVDD = DVDD = 5V
10
NUMBER OF DEVICES
1.21
1.19
6
4
2
05333-035
1.17
1.15
–40
8
–20
0
20
40
60
80
100
0
44.4
05333-026
VREF (V)
1.23
44.6
44.8
120
45.0
45.2
45.4
45.6
45.8
VOUT OFFSET (mV)
TEMPERATURE (°C)
Figure 19. Histogram of VOUT Offset
Figure 16. VREF vs. Temperature
0
2.0
1.9
–10
AVDD = DVDD = 2.3V
–20
AVDD = DVDD = 5V
1.6
1.5
–30
DVDD (on CAP/2.5V)
–40
–50
1.4
–60
1.3
–70
–20
0
20
40
60
80
100
120
–80
10
AVDD (on IOUT)
100
1k
10k
MODULATING FREQUENCY (Hz)
TEMPERATURE (°C)
Figure 20. PSSR
Figure 17. Wake-up Time vs. Temperature
Rev. C | Page 12 of 28
05333-033
ATTENUATION (dB)
1.7
05333-036
WAKE-UP TIME (ms)
1.8
1.2
–40
TA = 25°C
100mV p-p RIPPLE
NO DECOUPLING ON SUPPLIES
AVDD = DVDD = 5V
100k
1M
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
–120
–130
–140
–150
–160
–170
100
AD5930
0
–10
–20
–30
(dB)
–40
–50
–60
–70
1k
10k
05333-016
–80
05333-037
PHASE NOISE
Data Sheet
–90
–100
100k
f (Hz)
0
5M
RWB 1K
VWB 300
ST 50 SEC
FREQUENCY (Hz)
Figure 21. Output Phase Noise
Figure 24. fMCLK = 10 MHz; fOUT = 3.33 MHz = fMCLK/3,
Frequency Word = 555555
0
0
–10
–10
–20
–20
–30
–30
–40
–50
–60
–60
–70
–70
–80
–80
–90
–100
0
–90
–100
100k
RWB 100
VWB 30
05333-017
(dB)
–50
05333-014
(dB)
–40
0
160k
RWB 100
ST 100 SEC
Figure 25. fMCLK = 50 MHz;
fOUT = 12 kHz, Frequency Word = 000FBA
Figure 22. fMCLK = 10 MHz;
fOUT = 2.4 kHz, Frequency Word = 000FBA
0
0
–10
–10
–20
–20
–30
–30
–40
–50
–50
–60
–70
–70
–80
–80
05333-015
–60
–90
0
RWB 1K
5M
VWB 300
05333-018
(dB)
–40
(dB)
ST 200 SEC
FREQUENCY (Hz)
FREQUENCY (Hz)
–100
VWB 30
–90
–100
0
1.6M
RWB 100
ST 50 SEC
VWB 300
ST 200 SEC
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 26. fMCLK = 50 MHz;
fOUT = 120 kHz, Frequency Word = 009D49
Figure 23. fMCLK = 10 MHz;
fOUT = 1.43 MHz = fMCLK/7, Frequency Word = 249249
Rev. C | Page 13 of 28
Data Sheet
0
–10
–20
–20
–30
–30
–40
–40
–50
–50
–60
–60
–70
–70
–80
–80
–90
–100
0
–90
–100
25M
RWB 1K
VWB 300
05333-021
(dB)
0
–10
05333-019
(dB)
AD5930
ST 200 SEC
0
RWB 1K
FREQUENCY (Hz)
0
–10
–20
–20
–30
–30
–40
–40
–50
–50
–60
–60
–70
–70
–80
–80
–90
25M
RWB 1K
VWB 300
05333-022
(dB)
0
05333-020
(dB)
Figure 29. fMCLK = 50 MHz; fOUT = 7.143 MHz = fMCLK/7,
Frequency Word = 2492492
–10
0
ST 200 SEC
FREQUENCY (Hz)
Figure 27. fMCLK = 50 MHz;
fOUT = 1.2 MHz, Frequency Word = 0624DD
–100
25M
VWB 300
–90
–100
0
RWB 1K
ST 200 SEC
25M
VWB 300
ST 200 SEC
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 30. fMCLK = 50 MHz; fOUT = 16.667 MHz = fMCLK/3,
Frequency Word = 5555555
Figure 28. fMCLK = 50 MHz;
fOUT = 4.8 MHz, Frequency Word = 189374
Rev. C | Page 14 of 28
Data Sheet
AD5930
TERMINOLOGY
Integral Nonlinearity (INL)
This is the maximum deviation of any code from a straight line
passing through the endpoints of the transfer function. The
endpoints of the transfer function are zero scale and full scale.
The error is expressed in LSBs.
Differential Nonlinearity (DNL)
This is the difference between the measured and ideal 1 LSB
change between two adjacent codes in the DAC. A specified
differential nonlinearity of ±1 LSB maximum ensures
monotonicity.
Total Harmonic Distortion (THD)
THD is the ratio of the rms sum of harmonics to the rms value
of the fundamental. For the AD5930, THD is defined as
THD(dB) = 20 log
V 2 2 + V 3 2 + V 4 2 + V 5 2 + V6 2
V1
where:
V1 is the rms amplitude of the fundamental.
V2, V3, V4, V5, and V6 are the rms amplitudes of the second
through the sixth harmonic.
Output Compliance
The output compliance refers to the maximum voltage that can
be generated at the output of the DAC to meet the specifications. When voltages greater than that specified for the output
compliance are generated, the AD5930 may not meet the
specifications listed in the data sheet.
Spurious-Free Dynamic Range (SFDR)
Along with the frequency of interest, harmonics of the
fundamental frequency and images of these frequencies are
present at the output of a DDS device. The SFDR refers to the
largest spur or harmonic that is present in the band of interest.
The wide band SFDR gives the magnitude of the largest
harmonic or spur relative to the magnitude of the fundamental
frequency in the 0 to Nyquist bandwidth. The narrow band
SFDR gives the attenuation of the largest spur or harmonic in a
bandwidth of ±200 kHz about the fundamental frequency.
Signal-to-Noise Ratio (SNR)
SNR is the ratio of the rms value of the measured output signal
to the rms sum of all other spectral components below the
Nyquist frequency. The value for SNR is expressed in decibels.
Clock Feedthrough
There is feedthrough from the MCLK input to the analog
output. Clock feedthrough refers to the magnitude of the
MCLK signal relative to the fundamental frequency in the
AD5930’s output spectrum.
Rev. C | Page 15 of 28
AD5930
Data Sheet
THEORY OF OPERATION
The AD5930 is a general-purpose synthesized waveform
generator capable of providing digitally programmable
waveform sequences in both the frequency and time domain.
The device contains embedded digital processing to provide a
repetitive sweep of a user programmable frequency profile
allowing enhanced frequency control. Because the device is preprogrammable, it eliminates continuous write cycles from a
DSP/μcontroller in generating a particular waveform.
Triangular-Sweep Mode
In the case of a triangular sweep, the AD5930 repeatedly
sweeps between sweep start to sweep end, that is, from FSTART
incrementally to
FSTART + NINCR × Δf
and then returns to FSTART in a decremented manner (see
Figure 32).
The triangular-sweep cycle time is given by
In the auto-increment mode, a single pulse at the CTRL pin starts
and executes the frequency sweep. In the external increment
mode, the CTRL pin also starts the sweep, but the frequency
increment interval is determined by the time interval between
sequential 0/1 transitions on the CTRL pin. Furthermore, the
CTRL pin can be used to directly control the burst profile, where
during the input high time, the output waveform is present, and
during the input low time, the output is reset to midscale.
(1 + (2 × NINCR)) × tINT
FSTART
MIDSCALE
FSTART
FSTART + NINCR × ΔF
FSTART + ΔF
05333-010
The frequency profile is defined by the start frequency (FSTART),
the frequency increment (Δf) and the number of increments
per sweep (NINCR). The increment interval between frequency
increments, tINT, is either user programmable with the interval
automatically determined by the device (auto-increment mode),
or externally controlled via a hardware pin (external increment
mode). For automatic update, the interval profile can either be
for a fixed number of clock periods or for a fixed number of
output waveform cycles.
FSTART
FSTART + ΔF
Figure 32. Triangular-Sweep Profile
OUTPUT MODES
The AD5930 offers two possible output modes: continuous
output mode and burst output mode. Both of these modes are
illustrated in Figure 33.
tINT
CONTINUOUS
MODE
The frequency profile can be swept in two different modes: saw
sweep or triangular (up/down) sweep.
TBURST
BURST
MODE
Saw-Sweep Mode
In the case of a saw sweep, the AD5930 repeatedly
sweeps between sweep start to sweep end, that is, from
FSTART incrementally to
1
2
NUMBER STEP CHANGES
05333-011
THE FREQUENCY PROFILE
Figure 33. Continuous Mode and Burst Mode of the AD5930
FSTART + NINCR × Δf
Continuous Output Mode
and then returns directly to FSTART to begin again (see Figure 31).
In this mode, each frequency of the sweep is available for the
length of time programmed into the time interval (tINT) register.
This means the frequency swept output signal is continuously
available, and is therefore phase continuous at all frequency
increments.
This gives a saw-sweep cycle time of
(NINCR + 1) × tINT
To set up the AD5930 in continuous mode, the CW/BURST bit
(D7) in the control register must be set to 0. See the Activating
and Controlling the Sweep section for more details.
Burst Output Mode
FSTART
FSTART
FSTART + ΔF
FSTART + NINCR × ΔF
Figure 31. Saw-Sweep Profile
05333-009
MIDSCALE
In this mode, the AD5930 provides a programmable burst
of the waveform output for a fixed length of time (TBURST)
within the programmed increment interval (tINT). Then for
the remainder of the tINT interval, the output is reset to mid-
Rev. C | Page 16 of 28
Data Sheet
AD5930
scale and remains there until the next frequency increment.
This is beneficial for applications where the user needs to burst
a frequency for a set period, and then “listen” for a response
before increasing to the next frequency. Note also that the
beginning of each frequency increment is at midscale (Phase 0
Rad). Therefore, the phase of the signal is always known.
PROGRAMMING THE AD5930
To set up the AD5930 in burst mode, the CW/BURST bit (D7)
in the control register must be set to 1. See the Activating and
Controlling the Sweep section for more details about the burst
output mode.
Table 5. Register Addresses
The AD5930 is designed to provide automatic frequency sweeps
when the CTRL pin is triggered. The automatic sweep is
controlled by a set of registers, the addresses of which are given
in Table 5. The function of each register is described in more
detail in the following section.
Register Address
D15 D14 D13 D12
0
0
0
0
0
0
0
1
Mnemonic
CREG
NINCR
The AD5930 has a standard 3-wire serial interface, which is
compatible with SPI®, QSPI™, MICROWIRE™, and DSP
interface standards.
0
0
1
0
f
0
0
1
1
f
Data is loaded into the device as a 16-bit word under the
control of a serial clock input, SCLK. The timing diagram for
this operation is given in Figure 4.
0
1
1
1
0
1
0
0
tINT
TBURST
FSTART
The FSYNC input is a level-triggered input that acts as a frame
synchronization and chip enable. Data can only be transferred
into the device when FSYNC is low. To start the serial data
transfer, FSYNC should be taken low, observing the minimum
FSYNC to SCLK falling edge setup time, t7. After FSYNC goes
low, serial data is shifted into the device's input shift register on
the falling edges of SCLK for 16 clock pulses. FSYNC can be
taken high after the 16th falling edge of SCLK, observing the
minimum SCLK falling edge to FSYNC rising edge time, t8.
Alternatively, FSYNC can be kept low for a multiple of 16 SCLK
pulses, and then brought high at the end of the data transfer. In
this way, a continuous stream of 16-bit words can be loaded while
FSYNC is held low. FSYNC should only go high after the 16th
SCLK falling edge of the last word is loaded.
1
1
0
1
FSTART
1
1
1
1
1
1
0
1
The SCLK can be continuous, or, alternatively, the SCLK can
idle high or low between write operations.
Table 6. Control Register
SERIAL INTERFACE
POWERING UP THE AD5930
Name
Control bits
Number of
increments
Lower 12 bits of delta
frequency
Higher 12 bits of
delta frequency
Increment interval
Burst interval
Lower 12 bits of start
frequency
Higher 12 bits of start
frequency
Reserved
Reserved
The Control Register
The AD5930 contains a 12-bit control register (see Table 6) that
sets up the operating modes of the AD5930. The different
functions and the various output options from the AD5930 are
controlled by this register. Table 7 describes the individual bits
of the control register.
To address the control register, D15 to D12 of the 16-bit serial
word must be set to 0.
D15
0
When the AD5930 is powered up, the part is in an undefined
state, and therefore, must be reset before use. The eight registers
(control and frequency) contain invalid data and need to be set
to a known value by the user. The control register should be the
first register to be programmed, as this sets up the part. Note
that a write to the control register automatically resets the
internal state machines and provides an analog output of
midscale as it provides the same function as the INTERRUPT
pin. Typically, this is followed by a serial loading of all the
required sweep parameters. The DAC output remains at
midscale until a sweep is started using the CTRL pin.
Rev. C | Page 17 of 28
D14
0
D13
0
D12
0
D11 to D0
Control Bits
AD5930
Data Sheet
Table 7. Description of Bits in the Control Register
Bit
D15
to
D12
D11
Name
ADDR
Function
Register address bits.
B24
D10
DAC ENABLE
D9
SINE/TRI
D8
MSBOUTEN
D7
CW/BURST
D6
INT/EXT
BURST
D5
INT/EXT
INCR
D4
MODE
D3
SYNCSEL
D2
SYNCOUTEN
D1
D0
Reserved
Reserved
Two write operations are required to load a complete word into the FSTART register and the Δf register.
When B24 = 1, a complete word is loaded into a frequency register in two consecutive writes. The first write
contains the 12 LSBs of the frequency word and the next write contains the 12 MSBs. Refer to Table 5 for the
appropriate addresses. The write to the destination register occurs after both words have been loaded, so the
register never holds an intermediate value.
When B24 = 0, the 24-bit FSTART /Δf register operates as two 12-bit registers, one containing the 12 MSBs and the
other containing the 12 LSBs. This means that the 12 MSBs of the frequency word can be altered independent of
the 12 LSBs and vice versa. This is useful if the complete 24-bit update is not required. To alter the 12 MSBs or the
12 LSBs, a single write is made to the appropriate register address. Refer to Table 5 for the appropriate addresses.
When DAC ENABLE = 1, the DAC is enabled.
When DAC ENABLE = 0, the DAC is powered down. This saves power and is beneficial when only using the MSB of
the DAC input data (available at the MSBOUT pin).
The function of this bit is to control what is available at the IOUT/IOUTB pins.
When SINE/TRI = 1, the SIN ROM is used to convert the phase information into amplitude information resulting in a
sinusoidal signal at the output.
When SINE/TRI = 0, the SIN ROM is bypassed, resulting in a triangular (up-down) output from the DAC.
When MSBOUTEN = 1, the MSBOUT pin is enabled.
When MSBOUTEN = 0, the MSBOUT is disabled (tri-state).
When CW/BURST = 1, the AD5930 outputs each frequency continuously for the length of time or number of output
waveform cycles specified in the appropriate register, TBURST.
When CW/BURST = 0, the AD5930 bursts each frequency for the length of time/number of cycles specified in the
burst register, TBURST. For the remainder of the time within each increment window (TBURST − tINT), the AD5930
outputs a DC value of midscale. In external increment mode, it is defined by the pulse widths on the CTRL pin.
This bit is active when D7 = 0 and is also used in conjunction with D5. When the user is incrementing the frequency
externally (D5 = 1), D6 dictates whether the user is controlling the burst internally or externally.
When INT/EXT BURST = 1, the output burst is controlled externally through the CTRL pin. This is useful if the user is
using an external source to both trigger the frequency increments and determine the burst interval.
When INT/EXT BURST = 0, the output burst is controlled internally. The burst is pre-programmed by the user into
the TBURST register (the burst interval can either be clock-based or for a specified number of output cycles).
When D5 = 0, this bit is ignored.
When INT/EXT INCR = 1, the frequency increments are triggered externally through the CTRL pin.
When INT/EXT INCR = 0, the frequency increments are triggered automatically.
The function of this bit is to control what type of frequency sweep is carried out.
When MODE = 1, the frequency profile is a saw sweep.
When MODE = 0, the frequency profile is a triangular (up-down) sweep.
This bit is active when D2 = 1. It is user-selectable to pulse at the end of sweep (EOS) or at each frequency
increment.
When SYNCSEL = 1, the SYNCOP pin outputs a high level at the end of the sweep and returns to zero at the start of
the subsequent sweep.
When SYNCSEL= 0, the SYNCOP outputs a pulse of 4 × TCLOCK only at each frequency increment.
When SYNCOUTEN= 1, the SYNC output is available at the SYNCOP pin.
When SYNCOUTEN= 0, the SYNCOP pin is disabled (tri-state).
This bit must always be set to 1.
This bit must always be set to 1.
Rev. C | Page 18 of 28
Data Sheet
AD5930
SETTING UP THE FREQUENCY SWEEP
Number of Increments (NINCR)
As stated previously in The Frequency Profile section, the
AD5930 requires certain registers to be programmed to enable a
frequency sweep. The following sections discuss these registers
in more detail.
An end frequency, or a maximum/minimum frequency before
the sweep changes direction is not required on the AD5930.
Instead, this end frequency is calculated by multiplying the
frequency increment value (Δf) by the number of frequency
steps (NINCR), and adding it to/subtracting it from the start
frequency (FSTART), that is, FSTART + NINCR × Δf. The NINCR register
is a 12-bit register, with the address shown in Table 10.
Start Frequency (FSTART)
To start a frequency sweep, the user needs to tell the AD5930
what frequency to start sweeping from. This frequency is stored
in a 24-bit register called FSTART. If the user wishes to alter the
entire contents of the FSTART register, two consecutive writes
must be performed, one to the LSBs and the other to the MSBs.
Note that for an entire write to this register, the Control Bit B24
(D11) should be set to 1 with the LSBs programmed first.
In some applications, the user does not need to alter all 24 bits
of the FSTART register. By setting the Control Bit B24 (D11) to 0,
the 24-bit register operates as two 12-bit registers, one
containing the 12 MSBs and the other containing the 12 LSBs.
This means that the 12 MSBs of the FSTART word can be altered
independently of the 12 LSBs, and vice versa. The addresses of
both the LSBs and the MSBs of this register is given in Table 8.
Table 8. FSTART Register Bits
D15
1
1
D14
1
1
D13
0
0
D12
0
1
D11 to D0
12 LSBs of FSTART <11…0>
12 MSBs of FSTART <23…12>
Table 10. NINCR Register Bits
D15
0
D14
0
D13
0
D12
1
D11 to D0
12 bits of NINCR <11…0>
The number of increments is programmed in binary fashion,
with 000000000010 representing the minimum number of
frequency increments (2 increments), and 111111111111
representing the maximum number of increments (4095).
Table 11. NINCR Data Bits
D11
0000
0000
D0
0010
0000
0000
…
1111
1111
0000
0000
…
1111
1111
0011
0100
…
1110
1111
Number of Increments
2 frequency increments. This is the
minimum number of frequency
increments.
3 frequency increments.
4 frequency increments.
…
4094 frequency increments.
4095 frequency increments.
Frequency Increments (∆f)
Increment Interval (tINT)
The value in the Δf register sets the increment frequency for the
sweep and is added incrementally to the current output frequency.
Note that the increment frequency can be positive or negative,
thereby giving an increasing or decreasing frequency sweep.
The increment interval dictates the duration of the DAC output
signal for each individual frequency of the frequency sweep.
The AD5930 offers the user two choices:
At the start of a sweep, the frequency contained in the FSTART
register is output. Next, the frequency (FSTART + Δf ) is output.
This is followed by (FSTART + Δf + Δf) and so on. Multiplying the
Δf value by the number of increments (NINCR), and adding it to
the start frequency (FSTART), gives the final frequency in the
sweep. Mathematically this final frequency/stop frequency is
represented by
•
The duration is a multiple of cycles of the output frequency.
•
The duration is a multiple of MCLK periods.
This is selected by Bit D13 in the tINT register as shown in Table 12.
Table 12. tINT Register Bits
D15
0
D14
1
D13
0
D12
x
D11
x
0
1
1
x
x
FSTART + (NINCR × Δf).
The Δf register is a 23-bit register, and requires two 16-bit
writes to be programmed. Table 9 gives the addresses associated
with both the MSB and LSB registers of the Δf word.
Table 9. ∆f Register Bits
D15
0
D14
0
D13
1
D12
0
0
0
1
1
0
0
1
1
D11 D10 to D0
12 LSBs of ∆f
<11…0>
0
11 MSBs of
Δf <22…12>
1
11 MSBs of
Δf <22…12>
Sweep
Direction
N/A
Positive Δf
(FSTART + Δf )
Negative ∆f
(FSTART − Δf )
D10 to D0
11 bits <10…0>
Fixed number of output
waveform cycles.
11 bits <10…0>
Fixed number of clock
periods.
Programming of this register is in binary form with the
minimum number being decimal 2. Note in Table 12 that 11
bits, Bit D10 to Bit D0, of the register are available to program
the time interval. As an example, if MCLK = 50 MHz, then each
clock period/base interval is (1/50 MHz) = 20 ns. If each
frequency needs to be output for 100 ns, then <00000000101>
or decimal 5 needs to be programmed to this register. Note that
the AD5930 can output each frequency for a maximum
duration of 211 −1 (or 2047) times the increment interval.
Rev. C | Page 19 of 28
AD5930
Data Sheet
Therefore, in this example, a time interval of 20 ns × 2047 = 40 μs
is the maximum, with the minimum being 40 ns. For some
applications, this maximum time of 40 μs may be insufficient.
Therefore, to cater for sweeps that need a longer increment
interval, time-base multipliers are provided. Bit D12 and Bit D11
are dedicated to the time-base multipliers (see Table 12). A more
detailed table of the multiplier options is given in Table 13.
Table 13. Time-Base Multiplier Values
D12
0
0
1
1
D11
0
1
0
1
Table 14. TBURST Register Bits
D15
1
D14
0
D13
0
D12
x
D11
x
1
0
1
x
x
D10 to D0
11 bits of <0…10>
Fixed number of output
waveform cycles.
11 bits of <0…10>
Fixed number of clock
periods.
However, note that when using both the increment interval
(tINT) and burst time register (TBURST), the settings for Bit D13
should be the same. In instances where they differ, the AD5930
defaults to the value programmed into the tINT register.
Similarly, Bit 12 and Bit 11, the time-base multiplier bits, always
default to the value programmed into the tINT register.
Multiplier Value
Multiply (1/MCLK) by 1
Multiply (1/MCLK) by 5
Multiply (1/MCLK) by 100
Multiply (1/MCLK) by 500
If MCLK is 50 MHz and a multiplier of 500 is used, then the
base interval (TBASE) is now (1/(50 MHz) x 500)) = 10 μs. Using
a multiplier of 500, the maximum increment interval is 10 μs ×
211 − 1 = 20.5 ms. Therefore, the option of time-base multipliers
gives the user enhanced flexibility when programming the
length of the frequency window, because any frequency can be
output for a minimum of 40 ns up to a maximum of 20.5 ms.
Length of Sweep Time
The length of time to complete a user-programmed frequency
sweep is given by the following equation:
TSWEEP = (1 + NINCR) × TBASE
Burst Time Resister (TBURST)
As previously described in the Burst Output Mode section, the
AD5930 offers the user the ability to output each frequency in
the sweep for a length of time within the increment interval
(tINT), and then return to midscale for the remainder of the time
(tINT – TBURST) before stepping to the next frequency. The burst
option must be enabled. This is done by setting Bit D7 in the
control register to 0.
ACTIVATING AND CONTROLLING THE SWEEP
After the registers have been programmed, a 0 ≥ 1 transition on
the CTRL pin starts the sweep. The sweep always starts from
the frequency programmed into the FSTART register. It changes by
the value in the F register and increases by the number of
steps in the NINCR register. However, both the time interval and
burst duration of each frequency can be internally controlled
using the tINT and TBURST registers, or externally using the CTRL
pin. The options available are:

Auto-increment, auto-burst control

External increment, auto-burst control

External increment, external burst control
Auto-Increment, Auto-Burst Control
The values in the tINT and TBURST registers are used to control the
sweep. The AD5930 bursts each frequency for the length of
time programmed in the TBURST register, and outputs midscale
for the remainder of the interval time (tINT – TBURST).

A multiple of cycles of the output frequency
To set up the AD5930 to this mode, CW/BURST (Bit D7) in the
control register must be set to 0, INT/EXT BURST (Bit D6)
must be set to 0, and INT/EXT INCR (Bit D5) must be set to 0.
Note that if the part is only operating in continuous mode, then
(Bit D7) in the control register should be set to 1.

A multiple of MCLK periods
External Increment, Auto-Burst Control
Similar to the time interval register, the burst register can have
its duration as:
The address for this register is given in Table 14.
The time interval, tINT, is set by the pulse rate on the CTRL pin.
The first 0 ≥1 transition on the pin starts the sweep. Each
subsequent 0 ≥1 transition on the CTRL pin increments the
output frequency by the value programmed into the F register.
For each increment interval, the AD5930 outputs each
frequency for the length of time programmed into the TBURST
register, and outputs midscale until the CTRL pin is pulsed
again. Note that for this mode, the values programmed into Bit
D13, Bit D12, and bit D11 of the TBURST register are used.
Rev. C | Page 20 of 28
Data Sheet
AD5930
To setup the AD5930 to this mode, CW/BURST (Bit D7) in the
control register must be set to 0, INT/EXT BURST (Bit D6)
must be set to 0, and INT/EXT INCR (Bit D5) must be set to 1.
Note that if the part is only operating in continuous mode, then
Bit D7 in the control register should be set to 1.
OUTPUTS FROM THE AD5930
External Increment, External Burst Control
Analog Outputs
Sinusoidal Output
Interrupt Pin
This function is used as an interrupt during a frequency sweep.
A low-to-high transition on this pin is sampled by the internal
MCLK, thereby resetting internal state machines, which results
in the output going to midscale.
Standby Pin
Sections of the AD5930 that are not in use can be powered
down to minimize power consumption. This is done by using
the STANDBY pin. For the optimum power savings, it is
recommended to reset the AD5930 before entering standby,
because doing so reduces the power-down current to 20 µA.
When this pin is high, the internal MCLK is disabled, and the
reference, DAC, and regulator are powered down. When in this
state, the DAC output of the AD5930 remains at its present
value as the NCO is no longer accumulating. When the device
is taken back out of standby mode, the MCLK is re-activated
and the sweep continues. To ensure correct operation for new
data, it is recommended that the device be internally reset using
a control register write or using the INTERRUPT pin, and then
restarted.
Triangle Output
The SIN ROM can be bypassed so that the truncated digital
output from the NCO is sent to the DAC. In this case, the
output is no longer sinusoidal. The DAC produces a 10-bit
linear triangular function. To have a triangle output from the
IOUT/IOUTB pins, set Bit SINE/TRI (D9) to 0. Note that the
DAC ENABLE bit (D10) must be 1 (that is, the DAC is enabled)
when using these pins.
VOUT MAX
p/2
5p/2
9p/2
VOUT MIN
3p/2
7p/2
11p/2
05333-012
To setup the AD5930 to this mode, CW/BURST (Bit D7) in the
control register must be set to 0, INT/EXT BURST (Bit D6)
must be set to 1, and INT/EXT INCR (Bit D5) must be set to 1.
Note that if the part is only operating in continuous mode, then
Bit D7 in the control register should be set to 1.
The SIN ROM is used to convert the phase information from
the frequency register into amplitude information, which results
in a sinusoidal signal at the output. To have a sinusoidal output
from the IOUT/IOUTB pins, set Bit SINE/TRI (Bit D9) to 1.
Figure 34. Triangle Output
Digital Outputs
Square Wave Output from MSBOUT
The inverse of the MSB from the NCO can be output from the
AD5930. By setting the MSBOUTEN (D8) control bit to 1, the
inverted MSB of the DAC data is available at the MSBOUT pin.
This is useful as a digital clock source.
DVDD
05333-013
Both the increment interval (tINT) and the burst interval (TBURST)
are controlled by the CTRL pin. A 0 ≥ 1 transition on the CTRL
pin starts the sweep. The duration of CTRL high then dictates
the length of time the AD5930 bursts that frequency. The low
time of CTRL is the “listen” time, that is, how long the part
remains at midscale. Bringing the CTRL pin high again initiates a
frequency increment, and the pattern continues. For this mode,
the settings for Bit D13, Bit D12, and Bit D11 are ignored.
The AD5930 offers a variety of outputs from the chip. The analog
outputs are available from the IOUT/IOUTB pins, and include a
sine wave and a triangle output. The digital outputs are available
from the MSBOUT pin and the SYNCOUT pin.
DGND
Figure 35. MSB Output
SYNCOUT Pin
The SYNCOUT pin can be used to give the status of the sweep.
It is user selectable for the end of the sweep, or to output a 4 ×
TCLOCK pulse at frequency increments. The timing information
for both of these modes is shown in Figure 6 and Figure 7.
The SYNCOUT pin must be enabled before use. This is done
using Bit D2 in the control register. The output available from
this pin is then controlled by Bit D3 in the control register. See
Table 5 for more information.
Rev. C | Page 21 of 28
AD5930
Data Sheet
APPLICATIONS INFORMATION
The printed circuit board that houses the AD5930 should be
designed so that the analog and digital sections are separated
and confined to certain areas of the board. This facilitates the
use of ground planes that can be easily separated. A minimum
etch technique is generally best for ground planes because it
gives the best shielding. Digital and analog ground planes
should only be joined in one place. If the AD5930 is the only
device requiring an AGND to DGND connection, then the
ground planes should be connected at the AGND and DGND
pins of the AD5930. If the AD5930 is in a system where
multiple devices require AGND to DGND connections, the
connection should be made at one point only, a star ground
point that should be established as close as possible to the
AD5930.
Avoid running digital lines under the device as these couple
noise onto the die. The analog ground plane should be allowed
to run under the AD5930 to avoid noise coupling. The power
supply lines to the AD5930 should use as large a track as
possible to provide low impedance paths and reduce the effects
of glitches on the power supply line. Fast switching signals, such
as clocks, should be shielded with digital ground to avoid
radiating noise to other sections of the board. Avoid crossover
of digital and analog signals. Traces on opposite sides of the
board should run at right angles to each other. This reduces the
effects of feedthrough through the board. A microstrip
technique is by far the best, but is not always possible with a
double-sided board. In this technique, the component side of
the board is dedicated to ground planes, while signals are placed
on the other side.
Good decoupling is important. The analog and digital supplies
to the AD5930 are independent and separately pinned out to
minimize coupling between analog and digital sections of the
device. All analog and digital supplies should be decoupled to
AGND and DGND, respectively, with 0.1 μF ceramic capacitors
in parallel with 10 μF tantalum capacitors. To achieve the best
from the decoupling capacitors, they should be placed as close
as possible to the device, ideally right up against the device. In
systems where a common supply is used to drive both the
AVDD and DVDD of the AD5930, it is recommended that the
system’s AVDD supply be used. This supply should have the
recommended analog supply decoupling between the AVDD
pins of the AD5930 and AGND, and the recommended digital
supply decoupling capacitors between the DVDD pins and
DGND.
Proper operation of the comparator requires good layout
strategy. The strategy must minimize the parasitic capacitance
between VIN and the SIGN BIT OUT pin by adding isolation
using a ground plane. For example, in a multilayered board, the
VIN signal could be connected to the top layer and the SIGN
BIT OUT connected to the bottom layer, so that isolation is
provided between the power and ground planes.
Interfacing to Microprocessors
The AD5930 has a standard serial interface that allows the part
to interface directly with several microprocessors. The device
uses an external serial clock to write the data/control
information into the device. The serial clock can have a
frequency of 40 MHz maximum. The serial clock can be
continuous, or it can idle high or low between write operations.
When data/control information is being written to the AD5930,
FSYNC is taken low and is held low while the 16 bits of data are
being written into the AD5930. The FSYNC signal frames the
16 bits of information being loaded into the AD5930.
AD5930 TO ADSP-21467 INTERFACE
Figure 36 shows the serial interface between the AD5930 and
the ADSP-21467. The ADSP-21467 should be set up to operate
in the SPORT transmit alternate framing mode (TFSW = 1).
The ADSP-21467 is programmed through the SPORT control
register and should be configured as follows:
1.
Internal clock operation (ISCLK = 1)
2.
Active low framing (INVTFS = 1)
3.
16-bit word length (SLEN = 15)
4.
Internal frame sync signal (ITFS = 1)
5.
Generate a frame sync for each write (TFSR = 1)
Transmission is initiated by writing a word to the Tx register
after the SPORT has been enabled. The data is clocked out on
each rising edge of the serial clock and clocked into the AD5930
on the SCLK falling edge.
ADSP-214671
AD59301
TFS
FSYNC
DT
SDATA
SCLK
SCLK
1ADDITIONAL PINS OMITTED FOR CLARITY.
Figure 36. ADSP-21467 to AD5930 Interface
Rev. C | Page 22 of 28
05333-038
GROUNDING AND LAYOUT
Data Sheet
AD5930
AD5930 TO 68HC11/68L11 INTERFACE
Figure 37 shows the serial interface between the AD5930 and
the 68HC11/68L11 µcontroller. The µcontroller is configured as
the master by setting bit MSTR in the SPCR to 1, which
provides a serial clock on SCK while the MOSI output drives
the serial data line SDATA. Since the µcontroller does not have
a dedicated frame sync pin, the FSYNC signal is derived from a
port line (PC7). The setup conditions for correct operation of
the interface are as follows:
2.
Data is valid on the SCK falling edge (CPHA = 1)
80C51/80L511
When data is being transmitted to the AD5930, the FSYNC line
is taken low (PC7). Serial data from the 68HC11/68L11 is
transmitted in 8-bit bytes with only eight falling clock edges
occurring in the transmit cycle. Data is transmitted MSB first.
In order to load data into the AD5930, PC7 is held low after the
first 8 bits are transferred and a second serial write operation is
performed to the AD5930. Only after the second 8 bits have
been transferred should FSYNC be taken high again.
68HC11/68L111
FSYNC
SDATA
SCK
SCLK
05333-039
PC7
1ADDITIONAL
P3.3
FSYNC
RXD
SDATA
TXD
SCLK
1ADDITIONAL
PINS OMITTED FOR CLARITY.
Figure 38. 80C51/80L51 to AD5930 Interface
AD5930 TO DSP56002 INTERFACE
Figure 39 shows the interface between the AD5930 and the
DSP56002. The DSP56002 is configured for normal mode,
asynchronous operation with a gated internal clock (SYN = 0,
GCK = 1, SCKD = 1). The frame sync pin is generated internally
(SC2 = 1), the transfers are 16 bits wide (WL1 = 1, WL0 = 0), and
the frame sync signal frames the 16 bits (FSL = 0). The frame
sync signal is available on Pin SC2, but needs to be inverted
before being applied to the AD5930. The interface to the
DSP56000/DSP56001 is similar to that of the DSP56002.
AD59301
MOSI
AD59301
05333-040
SCK idles high between write operations (CPOL = 0)
PINS OMITTED FOR CLARITY.
Figure 37. 68HC11/68L11 to AD5930 Interface
AD5930 TO 80C51/80L51 INTERFACE
DSP560021
Figure 38 shows the serial interface between the AD5930 and
the 80C51/80L51 µcontroller. The µcontroller is operated in
mode 0 so that TXD of the 80C51/80L51 drives SCLK of the
AD5930, while RXD drives the serial data line SDATA. The
FSYNC signal is again derived from a bit programmable pin on
the port (P3.3 being used in the diagram). When data is to be
transmitted to the AD5930, P3.3 is taken low. The 80C51/80L51
transmits data in 8-bit bytes, thus, only eight falling SCLK edges
occur in each cycle. To load the remaining 8 bits to the AD5930,
P3.3 is held low after the first 8 bits have been transmitted, and
Rev. C | Page 23 of 28
AD59301
SC2
FSYNC
STD
SDATA
SCK
SCLK
05333-041
1.
a second write operation is initiated to transmit the second byte
of data. P3.3 is taken high following the completion of the
second write operation. SCLK should idle high between the two
write operations. The 80C51/80L51 outputs the serial data in an
LSB first format. The AD5930 accepts the MSB first (the 4
MSBs being the control information, the next 4 bits being the
address while the 8 LSBs contain the data when writing to a
destination register). Therefore, the transmit routine of the
80C51/80L51 must take this into account and rearrange the bits
so that the MSB is output first.
1ADDITIONAL
PINS OMITTED FOR CLARITY.
Figure 39. DSP56002 to AD5930 Interface
AD5930
Data Sheet
EVALUATION BOARD
Using the AD5930 Evaluation Board
The AD5930 evaluation board allows designers to evaluate the
high performance AD5930 DDS modulator with minimum
effort.
The AD5930 evaluation kit is a test system designed to simplify
the evaluation of the AD5930. An application note is also
available with the evaluation board and gives full information
on operating the evaluation board.
The evaluation board interfaces to the USB port of a PC. It is
possible to power the entire board off the USB port. All that is
needed to complete the evaluation of the chip is either a
spectrum analyzer or a scope.
The DDS evaluation kit includes a populated and tested
AD5930 printed circuit board. The EVAL-AD5930EB kit is
shipped with a CD-ROM that includes self-installing software.
The PC is connected to the evaluation board using the supplied
cable. The software is compatible with Microsoft® Windows®
2000 and Windows XP.
A schematic of the evaluation board is shown in Figure 40 and
Figure 41.
Prototyping Area
An area is available on the evaluation board for the user to add
additional circuits to the evaluation test set. Users may want to
build custom analog filters for the output or add buffers and
operational amplifiers to be used in the final application.
XO vs. External Clock
The AD5930 can operate with master clocks up to 50 MHz. A
50 MHz oscillator is included on the evaluation board.
However, this oscillator can be removed and, if required, an
external CMOS clock can be connected to the part.
Rev. C | Page 24 of 28
05333-023
SHIELD
T3
C28
0.1µF
3.3V
T4
VBUS
D–
D+
IO
GND
USB-MINI-B
J1
GROUND LINK
C30
0.1µF
1
2
3
4
5
T5
T6
3.3V
C33
0.1µF
C9
10µF
RTAJ_A
C32
0.1µF
+
K
T7
C34
0.1µF
C8
0.1µF
C0603
LED
IN1
IN2
SD
C35
0.1µF
8
7
5
1
U3
C36
0.1µF
4
VCC
2
WP
6
SCL
3
NR
GND
ADP3303-3.3
C5
0.1µF
C0603
3.3V
C4
0.1µF
C0603
R17
100kΩ
R0603
3.3V
STANDBY
INTERRUPT
CTRL
SDATA
SCLK
FSYNC
C3
0.1µF
C0603
R4
100kΩ
R0603
3.3V
C12
0.1µF
C0603
13
14
1
2
33
34
35
36
37
38
39
40
9
8
54
42
44
C7
0.1µF
C0603
+
C10
2.2µF
RTAJ_A
R17
0Ω
R0603
3.3V
3
IFCLK
RSVD
RDY0/*SLRD
RDY1/*SLWR
PA0/INT0
PA1/INT1
PA2/*SLOE
PA3/*WU2
PA4/FIFOADR0
PA5/FIFOADR1
PA6/*PKTEND
PA7/*FLD/SLCS
D–
D+
3.3V
PB0/FD0
PB1/FD1
PB2/FD2
PB3/FD3
PB4/FD4
PB5/FD5
PB6/FD6
PB7/FD7
PD0/FD8
PD1/FD9
PD2/FD10
PD3/FD11
PD4/FD12
PD5/FD13
PD6/FD14
PD7/FD15
XTALIN
XTALOUT
SDA
SCL
CTL0/*FLAGA
CTL1/*FLAGB
CTL2/*FLAGC
U4
CY7C68013-CS P
CLKOUT
RESET
*WAKEUP
AVCC
R3
1kΩ
R0603
AGND
1 GL2 2
VCC
VCC
VCC
VCC
VCC
VCC
VCC
7
11
17
27
32
43
55
6
Rev. C | Page 25 of 28
GND
GND
GND
GND
GND
GND
GND
Figure 40. Page 1 of EVAL-AD5930EB Schematic
10
12
26
28
41
53
56
02
A
5
4
16
15
29
30
31
18
19
20
21
22
23
24
25
45
46
47
48
49
50
51
52
C1
22pF
C0603
C2
22pF
C0603
+
8
C6
22pF
C0603
VCC
7
WP
6
SCL
5
SDA
SDA SCL
A0
A1
A2
VSS
24LC01
24MHz
Y1
1
2
3
4
3.3V
3.3V
C11
10µF
RTAJ_A
R2
2.2kΩ
R0603
R1
2.2kΩ
R0603
3.3V
Data Sheet
AD5930
SCHEMATIC
05333-024
J13
MCLK
J8
STANDBY
J7
INTERRUPT
J6
CTRL
C37
0.1µF
C0603
DVDD
A B
R9
49.9kΩ
R0603
LK6
A B
R12
10kΩ
R0603
LK6
A B
R11
10kΩ
R0603
LK5
A B
R10
10kΩ
R0603
LK4
A B
LK2
FSYNC
SCLK
SDATA
DVDD
J5
SDATA
R15
R0603
8
14
VDD
U7
50MHZ_XTAL
7
GND
O/P
STANDBY
STANDBY
INT
CTRL
INTERRUPT
CTRL
4
7
9
12
ADG774
S1A
D1
S2A
D2
D3
S3A
D4
S4A
IN EN GND
VDD
DVDD
2
5
11
14
16
J4
J3
1
SCLK
15
FSYNC
3
S1B
6
S2B
10
S3B
13
S4B
8
T25
SCLK
C17
0.1µF
C0603
SDATA
DVDD
8
13
12
17
15
14
16
DGND O/P
MCLK
INTERRUPT
STANDBY
CTRL
FSYNC
SCLK
SDATA
T26
AVDD
IOUT
DGND
AGND
MSBOUT
SYNCOUT
IOUTB
GL1
GROUND LINK
LK8
FS_A
C23
0.01µF
C0603
C21
C0603
AVDD
C31
0.1µF
C0603
B A
SURFACE MOUNT AREA
THROUGH HOLE AREA
10
9
19
20
2
3
1
C20
0.1µF
C0603
+
2
C29
10µF
RTAJ_A
DVDD
1
R16
1.5kΩ
C19
10µF
RTAJ_A
AVDD
FSADJUST
REF
COMP
DVDD
L1
BEAD
DVDD
U1
AD5930
LK7
C15
0.1µF
C0603
+
C16
10µF
RTAJ_A
CAP/2.5V
C13
10µF
RTAJ_A
3.3V
C17
0.1µF
C0603
C14
0.1µF
C0603
MCLK
FSYNC
J2–2
DGND
J2–1
A B
LK1
5
DVDD
4
T22
6
11
Rev. C | Page 26 of 28
7
Figure 41. Page 2 of EVAL-AD5930EB Schematic
18
T21
AVDD
R6
6.8kΩ
R0603
J14–2
AGND
J14–1
AVDD
T23
IOUTB
IOUT
T24
SYNCOUT
MSBOUT
C25
C0603
C24
C0603
REF
J12
IOUTB
J11
IOUT
J15
J10
C18
C0603
J9
SYNCOUT
C26
C0603
MSBOUT
R8
200Ω
R0603
R7
200Ω
R0603
C22
0.1µF
C0603
REF
AD5930
Data Sheet
Data Sheet
AD5930
OUTLINE DIMENSIONS
6.60
6.50
6.40
20
11
4.50
4.40
4.30
6.40 BSC
10
1
PIN 1
0.65
BSC
1.20 MAX
0.15
0.05
COPLANARITY
0.10
0.30
0.19
0.20
0.09
SEATING
PLANE
8°
0°
0.75
0.60
0.45
COMPLIANT TO JEDEC STANDARDS MO-153-AC
Figure 42. 20-Lead Thin Shrink Small Outline Package (TSSOP)
(RU-20)
Dimensions shown in millimeters
ORDERING GUIDE
Model1
AD5930YRUZ
AD5930YRUZ-REEL7
EVAL-AD5930EBZ
1
Temperature Range
−40°C to +125°C
−40°C to +125°C
Package Description
20-Lead Thin Shrink Small Outline Package [TSSOP]
20-Lead Thin Shrink Small Outline Package [TSSOP]
Evaluation Board
Z = RoHS Compliant Part.
Rev. C | Page 27 of 28
Package Option
RU-20
RU-20
AD5930
Data Sheet
NOTES
© 2005–2015 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05333-0-7/15(C)
Rev. C | Page 28 of 28
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement