AD AD5722 Complete, dual, 12-/14-/16-bit, serial input, unipolar/bipolar, voltage output dac Datasheet

Complete, Dual, 12-/14-/16-Bit, Serial
Input, Unipolar/Bipolar, Voltage Output DACs
AD5722/AD5732/AD5752
FEATURES
GENERAL DESCRIPTION
Complete, dual, 12-/14-/16-bit digital-to-analog converter (DAC)
Operates from single/dual supplies
Software programmable output range
+5 V, +10 V, +10.8 V, ±5 V, ±10 V, ±10.8 V
INL error: ±16 LSB maximum, DNL error: ±1 LSB maximum
Total unadjusted error (TUE): 0.1% FSR maximum
Settling time: 10 μs typical
Integrated reference buffers
Output control during power-up/brownout
Simultaneous updating via LDAC
Asynchronous CLR to zero scale or midscale
DSP-/microcontroller-compatible serial interface
24-lead TSSOP
Operating temperature range: −40°C to +85°C
iCMOS process technology1
The AD5722/AD5732/AD5752 are dual, 12-/14-/16-bit, serial
input, voltage output, digital-to-analog converters. They operate
from single-supply voltages from +4.5 V up to +16.5 V or dualsupply voltages from ±4.5 V up to ±16.5 V. Nominal full-scale
output range is software-selectable from +5 V, +10 V, +10.8 V,
±5 V, ±10 V, or ±10.8 V. Integrated output amplifiers, reference
buffers, and proprietary power-up/power-down control circuitry
are also provided.
The parts offer guaranteed monotonicity, integral nonlinearity
(INL) of ±16 LSB maximum, low noise, and 10 μs typical
settling time.
The AD5722/AD5732/AD5752 use a serial interface that
operates at clock rates up to 30 MHz and are compatible with
DSP and microcontroller interface standards. Double buffering
allows the simultaneous updating of all DACs. The input coding
is user-selectable twos complement or offset binary for a bipolar
output (depending on the state of Pin BIN/2sComp), and
straight binary for a unipolar output. The asynchronous clear
function clears all DAC registers to a user-selectable zero-scale
or midscale output. The parts are available in a 24-lead TSSOP
and offer guaranteed specifications over the −40°C to +85°C
industrial temperature range.
APPLICATIONS
Industrial automation
Closed-loop servo control, process control
Automotive test and measurement
Programmable logic controllers
The AD5722/AD5732/AD5752 are pin compatible with the
AD5724/AD5734/AD5754, which are complete, quad, 12-/14-/
16-bit, serial input, unipolar/bipolar voltage output DACs.
FUNCTIONAL BLOCK DIAGRAM
AVSS
REFIN
AD5722/AD5732/AD5752
REFERENCE
BUFFERS
CLR
BIN/2sCOMP
SDIN
SCLK
SYNC
12/14/16
INPUT SHIFT
REGISTER
AND
CONTROL
LOGIC
12/14/16
INPUT
REGISTER A
DAC
REGISTER A
INPUT
REGISTER B
12/14/16
DAC
REGISTER B
DAC A
VOUTA
DAC B
VOUTB
SDO
GND
LDAC
DAC_GND (2)
SIG_GND (2)
06467-001
DVCC
AVDD
Figure 1.
1
For analog systems designers within industrial/instrumentation equipment OEMs who need high performance ICs at higher voltage levels, iCMOS® is a technology
platform that enables the development of analog ICs capable of 30 V and operating at ±15 V supplies while allowing dramatic reductions in power consumption and
package size, as well as increased ac and dc performance.
Rev. D
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
www.analog.com
Fax: 781.461.3113 ©2008–2011 Analog Devices, Inc. All rights reserved.
AD5722/AD5732/AD5752
TABLE OF CONTENTS
Features .............................................................................................. 1
Transfer Function....................................................................... 20
Applications....................................................................................... 1
Input Shift Register .................................................................... 24
General Description ......................................................................... 1
DAC Register .............................................................................. 25
Functional Block Diagram .............................................................. 1
Output Range Select Register ................................................... 25
Revision History ............................................................................... 2
Control Register ......................................................................... 26
Specifications..................................................................................... 3
Power Control Register ............................................................. 26
AC Performance Characteristics ................................................ 5
Design Features............................................................................... 27
Timing Characteristics ................................................................ 5
Analog Output Control ............................................................. 27
Timing Diagrams.......................................................................... 6
Power-Down Mode.................................................................... 27
Absolute Maximum Ratings............................................................ 8
Overcurrent Protection ............................................................. 27
ESD Caution.................................................................................. 8
Thermal Shutdown .................................................................... 27
Pin Configuration and Function Descriptions............................. 9
Applications Information .............................................................. 28
Typical Performance Characteristics ........................................... 10
+5 V/±5 V Operation ................................................................ 28
Terminology .................................................................................... 16
Layout Guidelines....................................................................... 28
Theory of Operation ...................................................................... 18
Galvanically Isolated Interface ................................................. 28
Architecture................................................................................. 18
Voltage Reference Selection ...................................................... 28
Serial Interface ............................................................................ 18
Microprocessor Interfacing....................................................... 29
Load DAC (LDAC)..................................................................... 20
Outline Dimensions ....................................................................... 30
Asynchronous Clear (CLR)....................................................... 20
Ordering Guide .......................................................................... 30
Configuring the AD5722/AD5732/AD5752 .......................... 20
REVISION HISTORY
7/11—Rev. C to Rev. D
Changes to Table 3: t7, t8, t10 Limits......................................................5
3/11—Rev. B to Rev. C
Changes to Configuring the AD5722/AD5732/AD5752 Section..20
8/10—Rev. A to Rev. B
Changes to Table 27........................................................................ 26
5/10—Rev. 0 to Rev. A
Changes to Junction Temperature, TJ max Parameter, Table 4 .. 8
Changes to Exposed Paddle Description, Table 5 ........................ 9
Changes to Ordering Guide .......................................................... 30
10/08—Revision 0: Initial Version
Rev. D | Page 2 of 32
AD5722/AD5732/AD5752
SPECIFICATIONS
AVDD = 4.5 V 1 to 16.5 V; AVSS = −4.5 V1 to −16.5 V, or AVSS = 0 V; GND = 0 V; REFIN = 2.5 V; DVCC = 2.7 V to 5.5 V; RLOAD = 2 kΩ;
CLOAD = 200 pF; all specifications TMIN to TMAX, unless otherwise noted.
Table 1.
Parameter
ACCURACY
Resolution
AD5752
AD5732
AD5722
Total Unadjusted Error (TUE)
B Version
A Version
Integral Nonlinearity (INL) 2
AD5752 A, B Versions
AD5732 A Version
AD5722 A Version
Differential Nonlinearity (DNL)
Bipolar Zero Error
Min
Typ
Max
16
14
12
−0.1
−0.3
+0.1
+0.3
% FSR
% FSR
−16
−4
−1
−1
−6
+16
+4
+1
+1
+6
LSB
LSB
LSB
LSB
mV
+6
ppm FSR/°C
mV
+6
ppm FSR/°C
mV
ppm FSR/°C
% FSR
−6
Zero-Scale TC3
Offset Error
−6
Offset Error TC
Gain Error
−0.025
+0.025
Gain Error3
−0.065
0
Gain Error3
0
+0.08
Headroom Required
Output Voltage TC
Output Voltage Drift vs. Time
Short-Circuit Current
Load
Capacitive Load Stability
DC Output Impedance
±4
±4
±4
±4
1
−2
2
Test Conditions/Comments
Outputs unloaded
Bits
Bits
Bits
Bipolar Zero TC 3
Zero-Scale Error
Gain TC3
DC Crosstalk3
REFERENCE INPUT3
Reference Input Voltage
DC Input Impedance
Input Current
Reference Range
OUTPUT CHARACTERISTICS3
Output Voltage Range
Unit
2.5
5
±0.5
−10.8
−12
0.5
±4
±50
20
TA = 25°C, error at other temperatures obtained using
zero-scale TC
TA = 25°C, error at other temperatures obtained using
zero-scale TC
±10 V range, TA = 25°C, error at other temperatures
obtained using gain TC
+10 V and +5 V ranges, TA = 25°C, error at other
temperatures obtained using gain TC
±5 V range, TA = 25°C, error at other temperatures
obtained using gain TC
120
ppm FSR/°C
μV
±1% for specified performance
+2
3
V
MΩ
μA
V
V
V
V
ppm FSR/°C
ppm FSR
mA
kΩ
pF
Ω
AVDD/AVSS = ±11.7 V min, REFIN = +2.5 V
AVDD/AVSS = ±12.9 V min, REFIN = +3 V
+10.8
+12
0.9
2
4000
0.5
All models, all versions, guaranteed monotonic
TA = 25°C, error at other temperatures obtained
using bipolar zero TC
Rev. D | Page 3 of 32
Drift after 1000 hours of lifetest @ 125°C
For specified performance
AD5722/AD5732/AD5752
Parameter
DIGITAL INPUTS3
Input High Voltage, VIH
Input Low Voltage, VIL
Input Current
Pin Capacitance
DIGITAL OUTPUTS (SDO)3
Output Low Voltage, VOL
Output High Voltage, VOH
Output Low Voltage, VOL
Output High Voltage, VOH
High Impedance Leakage
Current
High Impedance Output
Capacitance
POWER REQUIREMENTS
AVDD
AVSS
DVCC
Power Supply Sensitivity3
∆VOUT/∆ΑVDD
AIDD
AISS
DICC
Power Dissipation
Power-Down Currents
AIDD
AISS
DICC
Min
Typ
Max
Unit
0.8
±1
V
V
μA
pF
2
5
0.4
V
V
V
V
μA
DVCC − 1
0.4
DVCC − 0.5
−1
+1
5
4.5
−4.5
2.7
40
40
300
Per pin
Per pin
DVCC = 5 V ± 10%, sinking 200 μA
DVCC = 5 V ± 10%, sourcing 200 μA
DVCC = 2.7 V to 3.6 V, sinking 200 μA
DVCC = 2.7 V to 3.6 V, sourcing 200 μA
pF
16.5
−16.5
5.5
V
V
V
3.25
2.4
2.5
3
190
79
dB
mA/channel
mA/channel
mA/channel
μA
mW
mW
−65
0.5
Test Conditions/Comments
DVCC = 2.7 V to 5.5 V, JEDEC compliant
Outputs unloaded
AVSS = 0 V, outputs unloaded
Outputs unloaded
VIH = DVCC, VIL = GND
±16.5 V operation, outputs unloaded
16.5 V operation, AVSS = 0 V, outputs unloaded
μA
μA
nA
1
For specified performance, the maximum headroom requirement is 0.9 V.
INL is the relative accuracy. It is measured from Code 512, Code 128, and Code 32 for the AD5752, the AD5732, and the AD5722, respectively.
3
Guaranteed by characterization; not production tested.
2
Rev. D | Page 4 of 32
AD5722/AD5732/AD5752
AC PERFORMANCE CHARACTERISTICS
AVDD = 4.5 V 1 to 16.5 V; AVSS = −4.5 V to −16.5 V, or AVSS = 0 V; GND = 0 V; REFIN = 2.5 V; DVCC = 2.7 V to 5.5 V; RLOAD = 2 kΩ;
CLOAD = 200 pF; all specifications TMIN to TMAX, unless otherwise noted.
Table 2.
Parameter 2
DYNAMIC PERFORMANCE
Output Voltage Settling Time
Min
Slew Rate
Digital-to-Analog Glitch Energy
Glitch Impulse Peak Amplitude
Digital Crosstalk
DAC-to-DAC Crosstalk
Digital Feedthrough
Output Noise
0.1 Hz to 10 Hz Bandwidth
100 kHz Bandwidth
Output Noise Spectral Density
1
2
Typ
Max
Unit
Test Conditions/Comments
10
7.5
12
8.5
5
20 V step to ±0.03% FSR
10 V step to ±0.03% FSR
512 LSB step settling (16-bit resolution)
3.5
13
35
10
10
0.6
μs
μs
μs
V/μs
nV-sec
mV
nV-sec
nV-sec
nV-sec
15
80
320
μV p-p
μV rms
nV/√Hz
0x8000 DAC code
Measured at 10 kHz, 0x8000 DAC code
For specified performance, the maximum headroom requirement is 0.9 V.
Guaranteed by design and characterization; not production tested.
TIMING CHARACTERISTICS
AVDD = 4.5 V to 16.5 V; AVSS = −4.5 V to −16.5 V, or AVSS = 0 V; GND = 0 V; REFIN = 2.5 V; DVCC = 2.7 V to 5.5 V; RLOAD = 2 kΩ; CLOAD =
200 pF; all specifications tMIN to tMAX, unless otherwise noted.
Table 3.
Parameter 1, 2, 3
t1
t2
t3
t4
t5
t6
t7
t8
t9
t10
t11
t12
t13
t14
t15 4
t164
t17
Limit at tMIN, tMAX
33
13
13
13
13
100
7
2
20
130
20
10
20
2.5
13
40
200
Unit
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
ns min
μs max
ns min
μs max
ns min
ns max
ns min
Description
SCLK cycle time
SCLK high time
SCLK low time
SYNC falling edge to SCLK falling edge setup time
SCLK falling edge to SYNC rising edge
Minimum SYNC high time (write mode)
Data setup time
Data hold time
LDAC falling edge to SYNC falling edge
SYNC rising edge to LDAC falling edge
LDAC pulse width low
DAC output settling time
CLR pulse width low
CLR pulse activation time
SYNC rising edge to SCLK falling edge
SCLK rising edge to SDO valid (CL SDO 5 = 15 pF)
Minimum SYNC high time (readback/daisy-chain mode)
1
Guaranteed by characterization; not production tested.
All input signals are specified with tR = tF = 5 ns (10% to 90% of DVCC) and timed from a voltage level of 1.2 V.
See Figure 2, Figure 3, and Figure 4.
4
Daisy-chain and readback mode.
5
CL SDO = capacitive load on SDO output.
2
3
Rev. D | Page 5 of 32
AD5722/AD5732/AD5752
TIMING DIAGRAMS
t1
SCLK
1
2
24
t2
t3
t6
t5
t4
SYNC
t8
t7
SDIN
DB0
DB23
t9
t11
t10
LDAC
t12
VOUTx
t12
VOUTx
t13
CLR
t14
06467-002
VOUTx
Figure 2. Serial Interface Timing Diagram
t1
SCLK
24
t3
t17
48
t2
t5
t15
t4
SYNC
t7
SDIN
t8
D32B
D0B
INPUT WORD FOR DAC N
D32B
D0B
t16
INPUT WORD FOR DAC N – 1
DB0
DB23
SDO
UNDEFINED
INPUT WORD FOR DAC N
t11
06467-003
LDAC
t10
Figure 3. Daisy-Chain Timing Diagram
Rev. D | Page 6 of 32
AD5722/AD5732/AD5752
SCLK
1
24
1
24
t17
SYNC
DB23
DB0
DB23
INPUT WORD SPECIFIES
REGISTER TO BE READ
SDO
DB23
DB0
NOP CONDITION
DB0
DB23
UNDEFINED
DB0
SELECTED REGISTER DATA
CLOCKED OUT
Figure 4. Readback Timing Diagram
Rev. D | Page 7 of 32
06467-004
SDIN
AD5722/AD5732/AD5752
ABSOLUTE MAXIMUM RATINGS
TA = 25°C unless otherwise noted.
Transient currents of up to 100 mA do not cause SCR latch-up.
Table 4.
Parameter
AVDD to GND
AVSS to GND
DVCC to GND
Digital Inputs to GND
Digital Outputs to GND
REFIN to GND
VOUTA or VOUTB to GND
DAC_GND to GND
SIG_GND to GND
Operating Temperature Range, TA
Industrial
Storage Temperature Range
Junction Temperature, TJ max
24-Lead TSSOP Package
θJA Thermal Impedance
θJC Thermal Impedance
Power Dissipation
Lead Temperature
Soldering
ESD (Human Body Model)
Rating
−0.3 V to +17 V
+0.3 V to −17 V
−0.3 V to +7 V
−0.3 V to DVCC + 0.3 V or 7 V
(whichever is less)
−0.3 V to DVCC + 0.3 V or 7 V
(whichever is less)
−0.3 V to +5 V
AVSS to AVDD
−0.3 V to +0.3 V
−0.3 V to +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
−40°C to +85°C
−65°C to +150°C
150°C
42°C/W
9°C/W
(TJ max − TA)/ θJA
JEDEC industry standard
J-STD-020
3.5 kV
Rev. D | Page 8 of 32
AD5722/AD5732/AD5752
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
24 AVDD
AVSS
1
NC
2
VOUTA
3
NC
4
BIN/2sCOMP
5
NC
6
20 SIG_GND
TOP VIEW
(Not to Scale) 19 DAC_GND
SYNC
7
18 DAC_GND
SCLK
8
17 REFIN
SDIN
9
16 SDO
LDAC 10
15 GND
NC 12
22 NC
21 SIG_GND
14 DVCC
13 NC
NOTES
1. NC = NO CONNECT
2. IT IS RECOMMENDED THAT THE
EXPOSED PAD BE THERMALLY
CONNECTED TO A COPPER PLANE
FOR ENHANCED THERMAL
PERFORMANCE.
06467-005
CLR 11
23 VOUTB
AD5722/
AD5732/
AD5752
Figure 5. Pin Configuration
Table 5. Pin Function Descriptions
Pin No.
1
Mnemonic
AVSS
2, 4, 6, 12,
13, 22
3
5
NC
7
SYNC
8
SCLK
9
10
SDIN
LDAC
11
14
15
16
CLR
DVCC
GND
SDO
17
18, 19
20, 21
23
24
Exposed
Paddle
REFIN
DAC_GND
SIG_GND
VOUTB
AVDD
VOUTA
BIN/2sCOMP
Description
Negative Analog Supply. Voltage ranges from −4.5 V to −16.5 V. This pin can be connected to 0 V if output
ranges are unipolar.
Do not connect to these pins.
Analog Output Voltage of DAC A. The output amplifier is capable of directly driving a 2 kΩ, 4000 pF load.
Determines the DAC coding for a bipolar output range. This pin should be hardwired to either DVCC or GND.
When hardwired to DVCC, input coding is offset binary. When hardwired to GND, input coding is twos
complement. (For unipolar output ranges, coding is always straight binary.)
Active Low Input. This is the frame synchronization signal for the serial interface. While SYNC is low, data is
transferred on the falling edge of SCLK. Data is latched on the rising edge of SYNC.
Serial Clock Input. Data is clocked into the shift register on the falling edge of SCLK. This operates at clock
speeds up to 30 MHz.
Serial Data Input. Data must be valid on the falling edge of SCLK.
Load DAC, Logic Input. This is used to update the DAC registers and, consequently, the analog outputs. When
this pin is tied permanently low, the addressed DAC register is updated on the rising edge of SYNC. If LDAC is
held high during the write cycle, the DAC input register is updated, but the output update is held off until the
falling edge of LDAC. In this mode, all analog outputs can be updated simultaneously on the falling edge of
LDAC. The LDAC pin should not be left unconnected.
Active Low Input. Asserting this pin sets the DAC registers to zero-scale code or midscale code (user-selectable).
Digital Supply. Voltage ranges from 2.7 V to 5.5 V.
Ground Reference.
Serial Data Output. Used to clock data from the serial register in daisy-chain or readback mode. Data is clocked
out on the rising edge of SCLK and is valid on the falling edge of SCLK.
External Reference Voltage Input. Reference input range is 2 V to 3 V. REFIN = 2.5 V for specified performance.
Ground Reference for the Two Digital-to-Analog Converters (DACs).
Ground Reference for the Two Output Amplifiers.
Analog Output Voltage of DAC B. The output amplifier is capable of directly driving a 2 kΩ, 4000 pF load.
Positive Analog Supply. Voltage ranges from 4.5 V to 16.5 V.
This exposed paddle should be connected to the potential of the AVSS pin, or alternatively, it can be left electrically
unconnected. It is recommended that the paddle be thermally connected to a copper plane for enhanced thermal
performance.
Rev. D | Page 9 of 32
AD5722/AD5732/AD5752
TYPICAL PERFORMANCE CHARACTERISTICS
6
0.6
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
4
= +12V/0V, RANGE = +10V
= ±12V, RANGE = ±10V
= ±6.5V, RANGE = ±5V
= +6.5V/0V, RANGE = +5V
0.4
0
–2
–0.4
–6
–0.6
0
10,000
20,000
30,000
40,000
50,000
60,000
CODE
1.5
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
1.0
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
–0.8
0
10,000
= +12V/0V, RANGE = +10V
= ±12V, RANGE = ±10V
= ±6.5V, RANGE = ±5V
= +6.5V/0V, RANGE = +5V
20,000
30,000
40,000
50,000
60,000
CODE
Figure 6. AD5752 Integral Nonlinearity Error vs. Code
Figure 9. AD5752 Differential Nonlinearity Error vs. Code
0.15
= +12V/0V, RANGE = +10V
= ±12V, RANGE = ±10V
= ±6.5V, RANGE = ±5V
= +6.5V/0V, RANGE = +5V
0.10
0.5
0
–0.5
0
–0.05
–1.0
–0.10
–1.5
–0.15
–2.0
0
2000
4000
6000
8000
10,000 12,000 14,000 16,000
CODE
–0.20
0
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
0.2
2000
= +12V/0V, RANGE = +10V
= ±12V, RANGE = ±10V
= ±6.5V, RANGE = ±5V
= +6.5V/0V, RANGE = +5V
4000
6000
8000
10,000 12,000 14,000 16,000
CODE
Figure 7. AD5732 Integral Nonlinearity Error vs. Code
0.3
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
06467-017
DNL ERROR (LSB)
0.05
06467-014
Figure 10. AD5732 Differential Nonlinearity Error vs. Code
0.04
= +12V/0V, RANGE = +10V
= ±12V, RANGE = ±10V
= ±6.5V, RANGE = ±5V
= +6.5V/0V, RANGE = +5V
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
0.03
= +12V/0V, RANGE = +10V
= ±12V, RANGE = ±10V
= ±6.5V, RANGE = ±5V
= +6.5V/0V, RANGE = +5V
0.02
DNL ERROR (LSB)
0.1
0
–0.1
–0.2
–0.3
0.01
0
–0.01
–0.02
–0.03
–0.4
–0.5
0
500
1000
1500
2000
2500
3000
3500
CODE
4000
06467-015
–0.04
Figure 8. AD5722 Integral Nonlinearity Error vs. Code
–0.05
0
500
1000
1500
2000
2500
3000
3500
4000
CODE
Figure 11. AD5722 Differential Nonlinearity Error vs. Code
Rev. D | Page 10 of 32
06467-018
INL ERROR (LSB)
–0.2
–4
–8
INL ERROR (LSB)
0
06467-016
DNL ERROR (LSB)
0.2
06467-013
INL ERROR (LSB)
2
AD5722/AD5732/AD5752
8
10
8
6
6
4
MAX INL ±10V
MAX INL ±5V
MIN INL ±10V
MIN INL ±5V
MAX INL +10V
MIN INL +10V
MAX INL +5V
MIN INL +5V
2
0
–2
INL ERROR (LSB)
INL ERROR (LSB)
4
2
BIPOLAR 5V MIN
UNIPOLAR 5V MIN
BIPOLAR 5V MAX
UNIPOLAR 5V MAX
0
–2
–4
–4
–6
–6
0
20
40
60
80
TEMPERATURE (°C)
06467-044
–20
–10
5.5
6.5
7.5
8.5
9.5
10.5 11.5 12.5 13.5 14.5 15.5 16.5
SUPPLY VOLTAGE (V)
Figure 12. AD5752 Integral Nonlinearity Error vs. Temperature
Figure 15. AD5752 Integral Nonlinearity Error vs. Supply Voltage
0.1
1.0
BIPOLAR 10V MIN
UNIPOLAR 10V MIN
BIPOLAR 10V MAX
UNIPOLAR 10V MAX
0.8
0
0.6
MAX DNL ±10V
MAX DNL ±5V
MIN DNL ±10V
MIN DNL ±5V
MAX DNL +10V
MIN DNL +10V
MAX DNL +5V
MIN DNL +5V
–0.2
–0.3
DNL ERROR (LSB)
DNL ERROR (LSB)
–0.1
06467-035
–8
–8
–40
–0.4
0.4
0.2
0
–0.2
–0.4
–0.6
–0.5
20
40
60
80
TEMPERATURE (°C)
–1.0
11.5
6
0.6
4
0.4
DNL ERROR (LSB)
0.8
2
BIPOLAR 10V MIN
UNIPOLAR 10V MIN
BIPOLAR 10V MAX
UNIPOLAR 10V MAX
–4
13.5
14.0
14.5
15.0
15.5
16.0
16.5
SUPPLY VOLTAGE (V)
15.0
15.5
16.0
16.5
Figure 14. AD5752 Integral Nonlinearity Error vs. Supply Voltage
BIPOLAR 5V MIN
UNIPOLAR 5V MIN
BIPOLAR 5V MAX
UNIPOLAR 5V MAX
–0.4
–0.8
13.0
14.5
0
–8
12.5
14.0
–0.2
–0.6
12.0
13.5
0.2
–6
06467-034
INL ERROR (LSB)
1.0
8
–10
11.5
13.0
Figure 16. AD5752 Differential Nonlinearity Error vs. Supply Voltage
10
0
12.5
SUPPLY VOLTAGE (V)
Figure 13. AD5752 Differential Nonlinearity Error vs. Temperature
–2
12.0
–1.0
5.5
6.5
7.5
8.5
9.5
10.5 11.5 12.5 13.5 14.5 15.5 16.5
SUPPLY VOLTAGE (V)
Figure 17. AD5752 Differential Nonlinearity Error vs. Supply Voltage
Rev. D | Page 11 of 32
06467-033
0
06467-045
–20
06467-032
–0.8
–0.6
–40
AD5722/AD5732/AD5752
6.0
0.02
5.5
0.01
5.0
BIPOLAR 10V MIN
UNIPOLAR 10V MIN
BIPOLAR 10V MAX
UNIPOLAR 10V MAX
4.5
AIDD (mA)
TUE (%)
0
–0.01
4.0
3.5
–0.02
3.0
–0.03
12.0
12.5
13.0
13.5
14.0
14.5
15.0
15.5
16.0
16.5
SUPPLY VOLTAGE (V)
2.0
4.5
06467-036
10.5
12.5
14.5
16.5
Figure 21. Supply Current vs. Supply Voltage (Single Supply)
0.04
4
+10V
0.03
3
0.01
ZERO-SCALE ERROR (mV)
0.02
TUE (%)
8.5
AVDD (V)
Figure 18. AD5752 Total Unadjusted Error vs. Supply Voltage
BIPOLAR 5V MIN
UNIPOLAR 5V MIN
BIPOLAR 5V MAX
UNIPOLAR 5V MAX
0
–0.01
–0.02
–0.03
2
1
±10V
0
–1
–2
–0.04
±5V
6.5
7.5
8.5
9.5
10.5 11.5 12.5 13.5 14.5 15.5 16.5
SUPPLY VOLTAGE (V)
–3
–40
06467-037
–0.05
5.5
6.5
–20
0
20
40
60
80
TEMPERATURE (°C)
Figure 19. AD5752 Total Unadjusted Error vs. Supply Voltage
06467-046
–0.04
11.5
06467-042
2.5
Figure 22. Zero-Scale Error vs. Temperature
0.8
5
0.6
4
AIDD (mA)
BIPOLAR ZERO ERROR (mV)
2
1
0
–1
AIDD (mA)
–2
±5V RANGE
0.2
0
±10V RANGE
–0.2
–0.4
–0.6
6.5
8.5
10.5
12.5
14.5
16.5
AVDD/AVSS (V)
Figure 20. Supply Current vs. Supply Voltage (Dual Supply)
–1.0
–40
–20
0
20
40
60
TEMPERATURE (°C)
Figure 23. Bipolar Zero Error vs. Temperature
Rev. D | Page 12 of 32
80
06467-047
–4
4.5
0.4
–0.8
–3
06467-038
AIDD/AISS (mA)
3
AD5722/AD5732/AD5752
0.06
15
±5V
10
OUTPUT VOLTAGE (V)
GAIN ERROR (% FSR)
0.04
0.02
0
±10V
–0.02
5
0
–5
+10V
–0.04
–20
0
20
40
60
–15
06467-048
–0.06
–40
80
TEMPERATURE (°C)
–3
–1
1
3
5
7
9
11
TIME (µs)
Figure 24. Gain Error vs. Temperature
06467-022
–10
Figure 27. Full-Scale Settling Time, ±10 V Range
1000
7
900
5
800
OUTPUT VOLTAGE (V)
700
DICC (µA)
600
500
400
DVCC = 5V
300
200
3
1
–1
–3
100
DVCC = 3V
–5
0
2
3
4
5
6
VLOGIC (V)
–7
–3
5
7
9
11
11
12
±5V RANGE, CODE = 0xFFFF
±10V RANGE, CODE = 0xFFFF
+10V RANGE, CODE = 0xFFFF
+5V RANGE, CODE = 0xFFFF
±5V RANGE, CODE = 0x0000
±10V RANGE, CODE = 0x0000
OUTPUT VOLTAGE (V)
10
0
–0.005
–0.010
8
6
4
2
–0.015
–0.020
–25
3
Figure 28. Full-Scale Settling Time, ±5 V Range
–20
–15
–10
–5
0
5
10
15
OUTPUT CURRENT (mA)
20
25
06467-040
OUTPUT VOLTAGE DELTA (V)
0.005
1
TIME (µs)
Figure 25. Digital Current vs. Logic Input Voltage
0.010
–1
06467-023
1
06467-024
0
06467-043
–100
Figure 26. Output Source and Sink Capability
0
–3
–1
1
3
5
7
9
TIME (µs)
Figure 29. Full-Scale Settling Time, +10 V Range
Rev. D | Page 13 of 32
AD5722/AD5732/AD5752
6
OUTPUT VOLTAGE (V)
5
4
3
1
2
–3
–1
1
3
5
7
9
RANGE = ±5V
RANGE = +5V
06467-025
0
11
TIME (µs)
CH1 5µV
Figure 30. Full-Scale Settling Time, +5 V Range
M5s
LINE
±
±10V RANGE, 0x7FFF
TO 0x8000
±10V RANGE, 0x8000 TO 0x7FFF
±5V RANGE, 0x7FFF TO 0x8000
±5V RANGE, 0x8000 TO 0x7FFF
+10V RANGE, 0x7FFF TO 0x8000
+10V RANGE, 0x8000 TO 0x7FFF
+5V RANGE, 0x7FFF TO 0x8000
+5V RANGE, 0x8000 TO 0x7FFF
0.010
AVDD/AVSS = ±16.5V
AVDD = +16.5V, AVSS = 0V
0.08
0.06
OUTPUT VOLTAGE (V)
0.015
73.8V
Figure 33. Peak-to-Peak Noise, 100 kHz Bandwidth
0.10
0.020
0.005
0
–0.005
0.04
0.02
0
–0.02
–0.010
0
1
2
3
4
5
TIME (µs)
–0.06
–50
06467-039
–0.015
–1
–30
–10
10
30
50
70
90
TIME (µs)
06467-041
–0.04
Figure 34. Output Glitch on Power-Up
Figure 31. Digital-to-Analog Glitch Energy
15
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
10
5
= +12V/0V, RANGE = +10V
= ±12V, RANGE = ±10V
= ±6.5V, RANGE = ±5V
= +6.5V/0V, RANGE = +5V
TUE (LSB)
0
1
–5
–10
–15
–20
–25
CH1 5µV
RANGE = +10V
RANGE = ±10V
M 5s
LINE
73.8V
–35
0
1000
2000
3000
4000
5000
6000
CODE
Figure 35. AD5752 Total Unadjusted Error vs. Code
Figure 32. Peak-to-Peak Noise, 0.1 Hz to 10 Hz Bandwidth
Rev. D | Page 14 of 32
06467-019
–30
RANGE = ±5V
RANGE = +5V
06467-026
OUTPUT VOLTAGE (V)
RANGE = +10V
RANGE = ±10V
06467-027
1
AD5722/AD5732/AD5752
4
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
2
1.0
= +12V/0V, RANGE = +10V
= ±12V, RANGE = ±10V
= ±6.5V, RANGE = ±5V
= +6.5V/0V, RANGE = +5V
0.5
0
= +12V/0V, RANGE = +10V
= ±12V, RANGE = ±10V
= ±6.5V, RANGE = ±5V
= +6.5V/0V, RANGE = +5V
–2
–4
–0.5
–1.0
–6
–1.5
–8
–2.0
–10
0
2000
4000
6000
8000
10000 12000 14000 16000
CODE
Figure 36. AD5732 Total Unadjusted Error vs. Code
–2.5
0
500
1000
1500
2000
2500
3000
3500
CODE
Figure 37. AD5722 Total Unadjusted Error vs. Code
Rev. D | Page 15 of 32
4000
06467-021
TUE (LSB)
0
06467-020
TUE (LSB)
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
AVDD/AVSS
AD5722/AD5732/AD5752
TERMINOLOGY
Relative Accuracy or Integral Nonlinearity (INL)
For the DAC, relative accuracy, or integral nonlinearity, is a
measure of the maximum deviation in LSBs from a straight line
passing through the endpoints of the DAC transfer function. A
typical INL vs. code plot can be seen in Figure 6.
Differential Nonlinearity (DNL)
Differential nonlinearity is the difference between the measured
change and the ideal 1 LSB change between any two adjacent
codes. A specified differential nonlinearity of ±1 LSB maximum
ensures monotonicity. This DAC is guaranteed monotonic by
design. A typical DNL vs. code plot can be seen in Figure 9.
Monotonicity
A DAC is monotonic if the output either increases or remains
constant for increasing digital input code. The AD5722/
AD5732/AD5752 are monotonic over their full operating
temperature range.
Bipolar Zero Error
Bipolar zero error is the deviation of the analog output from the
ideal half-scale output of 0 V when the DAC register is loaded
with 0x8000 (straight binary coding) or 0x0000 (twos complement
coding). A plot of bipolar zero error vs. temperature can be seen
in Figure 23.
Bipolar Zero TC
Bipolar zero TC is a measure of the change in the bipolar zero
error with a change in temperature. It is expressed in ppm FSR/°C.
Zero-Scale Error or Negative Full-Scale Error
Zero-scale error is the error in the DAC output voltage when
0x0000 (straight binary coding) or 0x8000 (twos complement
coding) is loaded to the DAC register. Ideally, the output voltage
should be negative full-scale − 1 LSB. A plot of zero-scale error
vs. temperature can be seen in Figure 22.
Zero-Scale TC
Zero-scale TC is a measure of the change in zero-scale error with a
change in temperature. Zero-scale TC is expressed in ppm FSR/°C.
Output Voltage Settling Time
Output voltage settling time is the amount of time required for
the output to settle to a specified level for a full-scale input change.
A plot for full-scale settling time can be seen in Figure 27.
Slew Rate
The slew rate of a device is a limitation in the rate of change of
the output voltage. The output slewing speed of a voltage output
DAC is usually limited by the slew rate of the amplifier used at
its output. Slew rate is measured from 10% to 90% of the output
signal and is given in V/μs.
Gain Error
Gain error is a measure of the span error of the DAC. It is the
deviation in slope of the DAC transfer characteristic from the
ideal and is expressed in % FSR. A plot of gain error vs.
temperature can be seen in Figure 24.
Gain TC
Gain TC is a measure of the change in gain error with changes
in temperature. Gain TC is expressed in ppm FSR/°C.
Total Unadjusted Error (TUE)
Total unadjusted error is a measure of the output error taking
all the various errors into account, namely INL error, offset
error, gain error, and output drift over supplies, temperature,
and time. TUE is expressed in % FSR.
Digital-to-Analog Glitch Impulse
Digital-to-analog glitch impulse is the impulse injected into the
analog output when the input code in the DAC register changes
state, but the output voltage remains constant. It is normally
specified as the area of the glitch in nV-sec and is measured
when the digital input code is changed by 1 LSB at the major
carry transition (0x7FFF to 0x8000). See Figure 31.
Glitch Impulse Peak Amplitude
Glitch impulse peak amplitude is the peak amplitude of the
impulse injected into the analog output when the input code in
the DAC register changes state. It is specified as the amplitude
of the glitch in mV and is measured when the digital input code
is changed by 1 LSB at the major carry transition (0x7FFF to
0x8000). See Figure 31.
Digital Feedthrough
Digital feedthrough is a measure of the impulse injected into
the analog output of the DAC from the digital inputs of the
DAC but is measured when the DAC output is not updated. It is
specified in nV-sec and measured with a full-scale code change
on the data bus.
Power Supply Sensitivity
Power supply sensitivity indicates how the output of the DAC is
affected by changes in the power supply voltage. It is measured
by superimposing a 50 Hz/60 Hz, 200 mV p-p sine wave on the
supply voltages and measuring the proportion of the sine wave
that transfers to the outputs.
Rev. D | Page 16 of 32
AD5722/AD5732/AD5752
DC Crosstalk
This is the dc change in the output level of one DAC in response
to a change in the output of another DAC. It is measured with a
full-scale output change on one DAC while monitoring another
DAC. It is expressed in LSBs.
Digital Crosstalk
Digital crosstalk is a measure of the impulse injected into the
analog output of one DAC from the digital inputs of another
DAC but is measured when the DAC output is not updated. It is
specified in nV-sec and measured with a full-scale code change
on the data bus.
DAC-to-DAC Crosstalk
DAC-to-DAC crosstalk is the glitch impulse transferred to the
output of one DAC due to a digital code change and a subsequent
output change of another DAC. This includes both digital and
analog crosstalk. It is measured by loading one of the DACs
with a full-scale code change (all 0s to all 1s and vice versa) with
LDAC low and monitoring the output of another DAC. The
energy of the glitch is expressed in nV-sec.
Rev. D | Page 17 of 32
AD5722/AD5732/AD5752
THEORY OF OPERATION
REFIN
The AD5722/AD5732/AD5752 are dual, 12-/14-/16-bit, serial
input, unipolar/bipolar, voltage output DACs. They operate
from unipolar supply voltages of +4.5 V to +16.5 V or bipolar
supply voltages of ±4.5 V to ±16.5 V. In addition, the parts have
software-selectable output ranges of +5 V, +10 V, +10.8 V, ±5 V,
±10 V, and ±10.8 V. Data is written to the AD5722/AD5732/
AD5752 in a 24-bit word format via a 3-wire serial interface.
The devices also offer an SDO pin to facilitate daisy-chaining
or readback.
R
R
TO OUTPUT
AMPLIFIER
R
The AD5722/AD5732/AD5752 incorporate a power-on reset
circuit to ensure that the DAC registers power up loaded with
0x0000. When powered on, the outputs are clamped to 0 V via
a low impedance path.
R
ARCHITECTURE
The DAC architecture consists of a string DAC followed by an
output amplifier. Figure 38 shows a block diagram of the DAC
architecture. The reference input is buffered before being
applied to the DAC.
06467-007
R
Figure 39. Resistor String Structure
REFIN
Output Amplifiers
The output amplifiers are capable of generating both unipolar
and bipolar output voltages. They are capable of driving a load
of 2 kΩ in parallel with 4000 pF to GND. The source and sink
capabilities of the output amplifiers can be seen in Figure 26.
The slew rate is 3.5 V/μs with a full-scale settling time of 10 μs.
REF (+)
RESISTOR
STRING
REF (–)
VOUTX
CONFIGURABLE
OUTPUT
AMPLIFIER
GND
OUTPUT
RANGE CONTROL
06467-006
DAC REGISTER
Figure 38. DAC Architecture Block Diagram
The resistor string structure is shown in Figure 39. It is a string
of resistors, each of value R. The code loaded to the DAC register
determines the node on the string where the voltage is to be
tapped off and fed into the output amplifier. The voltage is
tapped off by closing one of the switches connecting the string
to the amplifier. Because it is a string of resistors, it is guaranteed
monotonic.
Reference Buffers
The AD5722/AD5732/AD5752 require an external reference
source. The reference input has an input range of 2 V to 3 V,
with 2.5 V for specified performance. This input voltage is then
buffered before it is applied to the DAC cores.
SERIAL INTERFACE
The AD5722/AD5732/AD5752 are controlled over a versatile
3-wire serial interface that operates at clock rates up to 30 MHz.
It is compatible with SPI, QSPI™, MICROWIRE™, and DSP
standards.
Input Shift Register
The input shift register is 24 bits wide. Data is loaded into the
device MSB first as a 24-bit word under the control of a serial
clock input, SCLK. The input register consists of a read/write
bit, three register select bits, three DAC address bits, and 16 data
bits. The timing diagram for this operation is shown in Figure 2.
Rev. D | Page 18 of 32
AD5722/AD5732/AD5752
Standalone Operation
Daisy-Chain Operation
The serial interface works with both a continuous and noncontinuous serial clock. A continuous SCLK source can be used
only if SYNC is held low for the correct number of clock cycles.
In gated clock mode, a burst clock containing the exact number
of clock cycles must be used, and SYNC must be taken high
after the final clock to latch the data. The first falling edge of
SYNC starts the write cycle. Exactly 24 falling clock edges must
be applied to SCLK before SYNC is brought high again. If
SYNC is brought high before the 24th falling SCLK edge, the
data written is invalid. If more than 24 falling SCLK edges are
applied before SYNC is brought high, the input data is also
invalid. The input register addressed is updated on the rising
edge of SYNC. For another serial transfer to take place, SYNC
must be brought low again. After the end of the serial data
transfer, data is automatically transferred from the input shift
register to the addressed register.
For systems that contain several devices, the SDO pin can be
used to daisy-chain several devices together. Daisy-chain mode
can be useful in system diagnostics and in reducing the number
of serial interface lines. The first falling edge of SYNC starts the
write cycle. SCLK is continuously applied to the input shift
register when SYNC is low. If more than 24 clock pulses are
applied, the data ripples out of the shift register and appears on
the SDO line. This data is clocked out on the rising edge of
SCLK and is valid on the falling edge. By connecting the SDO
of the first device to the SDIN input of the next device in the
chain, a multidevice interface is constructed. Each device in the
system requires 24 clock pulses. Therefore, the total number of
clock cycles must equal 24 × N, where N is the total number of
AD5722/AD5732/AD5752 devices in the chain. When the serial
transfer to all devices is complete, SYNC is taken high. This
latches the input data in each device in the daisy chain and
prevents any further data from being clocked into the input shift
register. The serial clock can be a continuous or a gated clock.
When the data has been transferred into the chosen register of
the addressed DAC, all DAC registers and outputs can be
updated by taking LDAC low while SYNC is high.
AD5722/
AD5732/
AD5752*
68HC11*
MOSI
SDIN
SCK
SCLK
PC7
SYNC
PC6
LDAC
Readback Operation
Readback mode is invoked by setting the R/W bit = 1 in the
write operation to the serial input shift register. (If the SDO
output is disabled via the SDO disable bit in the control register,
it is automatically enabled for the duration of the read operation,
after which it is disabled again.) With R/W = 1, Bit A2 to Bit A0,
in association with Bit REG2 to Bit REG0, select the register to
be read. The remaining data bits in the write sequence are don’t
care bits. During the next SPI write, the data appearing on the SDO
output contains the data from the previously addressed register.
For a read of a single register, the NOP command can be used in
clocking out the data from the selected register on SDO. The
readback diagram in Figure 4 shows the readback sequence.
For example, to read back the DAC register of Channel A, the
following sequence should be implemented:
SDO
MISO
A continuous SCLK source can only be used if SYNC is held
low for the correct number of clock cycles. In gated clock mode,
a burst clock containing the exact number of clock cycles must
be used, and SYNC must be taken high after the final clock to
latch the data.
SDIN
AD5722/
AD5732/
AD5752*
SCLK
SYNC
LDAC
SDO
SDIN
AD5722/
AD5732/
AD5752*
1.
SCLK
SYNC
LDAC
*ADDITIONAL
PINS OMITTED FOR CLARITY.
06467-008
SDO
2.
Figure 40. Daisy Chaining the AD5722/AD5732/AD5752
Rev. D | Page 19 of 32
Write 0x800000 to the AD5722/AD5732/AD5752 input
register. This configures the part for read mode with the
DAC register of Channel A selected. Note that all the data
bits, DB15 to DB0, are don’t care bits.
Follow this with a second write, a NOP condition, 0x180000.
During this write, the data from the register is clocked out
on the SDO line.
AD5722/AD5732/AD5752
LOAD DAC (LDAC)
CONFIGURING THE AD5722/AD5732/AD5752
After data has been transferred into the input register of the
DACs, there are two ways to update the DAC registers and DAC
outputs. Depending on the status of both SYNC and LDAC, one
of two update modes is selected: individual DAC updating or
simultaneous updating of all DACs.
When the power supplies are applied to the AD5722/AD5732/
AD5752, the power-on reset circuit ensures that all registers
default to 0. This places all channels in power-down mode. The
DVCC should be brought high before any of the interface lines
are powered. If this is not done the first write to the device may
be ignored. The first communication to the AD5722/AD5732/
AD5752 should be to set the required output range on all
channels (the default range is the 5 V unipolar range) by writing
to the output range select register. The user should then write to
the power control register to power on the required channels. To
program an output value on a channel, that channel must first
be powered up; any writes to a channel while it is in power-down
mode are ignored. The AD5722/ AD5732/AD5752 operate with a
wide power supply range. It is important that the power supply
applied to the parts provide adequate headroom to support the
chosen output ranges.
OUTPUT
AMPLIFIER
REFIN
12-/14-/16-BIT
DAC
LDAC
DAC
REGISTER
VOUTX
SCLK
SYNC
SDIN
INTERFACE
LOGIC
SDO
06467-009
INPUT
REGISTER
TRANSFER FUNCTION
Figure 41. Simplified Diagram of Input Loading Circuitry for One DAC
Individual DAC Updating
In this mode, LDAC is held low while data is clocked into the
input shift register. The addressed DAC output is updated on
the rising edge of SYNC.
Simultaneous Updating of All DACs
In this mode, LDAC is held high while data is clocked into the
input shift register. All DAC outputs are asynchronously updated
by taking LDAC low after SYNC has been taken high. The
update now occurs on the falling edge of LDAC.
ASYNCHRONOUS CLEAR (CLR)
CLR is an active low clear that allows the outputs to be cleared
to either zero-scale code or midscale code. The clear code value is
user-selectable via the CLR select bit of the control register (see
the Control Register section). It is necessary to maintain CLR low
for a minimum amount of time to complete the operation (see
Figure 2). When the CLR signal is returned high, the output
remains at the cleared value until a new value is programmed.
The outputs cannot be updated with a new value while the CLR
pin is low. A clear operation can also be performed via the clear
command in the control register.
Table 7 to Table 15 show the relationships of the ideal input
code to output voltage for the AD5752, AD5732, and AD5722,
respectively, for all output voltage ranges. For unipolar output
ranges, the data coding is straight binary. For bipolar output
ranges, the data coding is user selectable via the BIN/2sCOMP
pin and can be either offset binary or twos complement.
For a unipolar output range, the output voltage expression is
given by
D
VOUT = VREFIN × Gain ⎡⎢ N ⎤⎥
⎣2 ⎦
For a bipolar output range, the output voltage expression is given by
D
VOUT = VREFIN × Gain ⎡⎢ N
⎣2
⎤ − Gain × VREFIN
⎥⎦
2
where:
D is the decimal equivalent of the code loaded to the DAC.
N is the bit resolution of the DAC.
VREFIN is the reference voltage applied at the REFIN pin.
Gain is an internal gain whose value depends on the output
range selected by the user, as shown in Table 6.
Table 6. Internal Gain Values
Output Range (V)
+5
+10
+10.8
±5
±10
±10.8
Rev. D | Page 20 of 32
Gain Value
2
4
4.32
4
8
8.64
AD5722/AD5732/AD5752
Ideal Output Voltage to Input Code Relationship—AD5752
Table 7. Bipolar Output, Offset Binary Coding
Digital Input
MSB
1111
1111
…
1000
1000
0111
…
0000
0000
1111
1111
…
0000
0000
1111
…
0000
0000
1111
1111
…
0000
0000
1111
…
0000
0000
LSB
1111
1110
…
0001
0000
1111
…
0001
0000
±5 V Output Range
+2 × REFIN × (32,767/32,768)
+2 × REFIN × (32,766/32,768)
…
+2 × REFIN × (1/32,768)
0V
−2 × REFIN × (1/32,768)
…
−2 × REFIN × (32,766/32,768)
−2 × REFIN × (32,767/32,768
Analog Output
±10 V Output Range
+4 × REFIN × (32,767/32,768)
+4 × REFIN × (32,766/32,768)
…
+4 × REFIN × (1/32,768)
0V
−4 × REFIN × (1/32,768)
…
−4 × REFIN × (32,766/32,768)
−4 × REFIN × (32,767/32,768)
±10.8 V Output Range
+4.32 × REFIN × (32,767/32,768)
+4.32 × REFIN × (32,766/32,768)
…
+4.32 × REFIN × (1/32,768)
0V
−4.32 × REFIN × (32,766/32,768)
…
−4.32 × REFIN × (32,766/32,768)
−4.32 × REFIN × (32,767/32,768)
Analog Output
±10 V Output Range
+4 × REFIN × (32,767/32,768)
+4 × REFIN × (32,766/32,768)
…
+4 × REFIN × (1/32,768)
0V
−4 × REFIN × (1/32,768)
…
−4 × REFIN × (32,766/32,768)
−4 × REFIN × (32,767/32,768)
±10.8 V Output Range
+4.32 × REFIN × (32,767/32,768)
+4.32 × REFIN × (32,766/32,768)
…
+4.32 × REFIN × (1/32,768)
0V
−4.32 × REFIN × (1/32,768)
…
−4.32 × REFIN × (32,766/32,768)
−4.32 × REFIN × (32,767/32,768)
Analog Output
+10 V Output Range
+4 × REFIN × (65,535/65,536)
+4 × REFIN × (65,534/65,536)
…
+4 × REFIN × (32,769/65,536)
+4 × REFIN × (32,768/65,536)
+4 × REFIN × (32,767/65,536)
…
+4 × REFIN × (1/65,536)
0V
+10.8 V Output Range
+4.32 × REFIN × (65,535/65,536)
+4.32 × REFIN × (65,534/65,536)
…
+4.32 × REFIN × (32,769/65,536)
+4.32 × REFIN × (32,768/65,536)
+4.32 × REFIN × (32,767/65,536)
…
+4.32 × REFIN × (1/65,536)
0V
Table 8. Bipolar Output, Twos Complement Coding
Digital Input
MSB
0111
0111
…
0000
0000
1111
…
1000
1000
1111
1111
…
0000
0000
1111
…
0000
0000
1111
1111
…
0000
0000
1111
…
0000
0000
LSB
1111
1110
…
0001
0000
1111
…
0001
0000
±5 V Output Range
+2 × REFIN × (32,767/32,768)
+2 × REFIN × (32,766/32,768)
…
+2 × REFIN × (1/32,768)
0V
−2 × REFIN × (1/32,768)
…
−2 × REFIN × (32,766/32,768)
−2 × REFIN × (32,767/32,768)
Table 9. Unipolar Output, Straight Binary Coding
Digital Input
MSB
1111
1111
…
1000
1000
0111
…
0000
0000
1111
1111
…
0000
0000
1111
…
0000
0000
1111
1111
…
0000
0000
1111
…
0000
0000
LSB
1111
1110
…
0001
0000
1111
…
0001
0000
+5 V Output Range
+2 × REFIN × (65,535/65,536)
+2 × REFIN × (65,534/65,536)
…
+2 × REFIN × (32,769/65,536)
+2 × REFIN × (32,768/65,536)
+2 × REFIN × (32,767/65,536)
…
+2 × REFIN × (1/65,536)
0V
Rev. D | Page 21 of 32
AD5722/AD5732/AD5752
Ideal Output Voltage to Input Code Relationship—AD5732
Table 10. Bipolar Output, Offset Binary Coding
Digital Input
MSB
11
11
…
10
10
01
…
00
00
1111
1111
…
0000
0000
1111
…
0000
0000
1111
1111
…
0000
0000
1111
…
0000
0000
LSB
1111
1110
…
0001
0000
1111
…
0001
0000
±5 V Output Range
+2 × REFIN × (8191/8192)
+2 × REFIN × (8190/8192)
…
+2 × REFIN × (1/8192)
0V
−2 × REFIN × (1/8192)
…
−2 × REFIN × (8190/8192)
−2 × REFIN × (8191/8191)
Analog Output
±10 V Output Range
+4 × REFIN × (8191/8192)
+4 × REFIN × (8190/8192)
…
+4 × REFIN × (1/8192)
0V
−4 × REFIN × (1/8192)
…
−4 × REFIN × (8190/8192)
−4 × REFIN × (8191/8192)
±10.8 V Output Range
+4.32 × REFIN × (8191/8192)
+4.32 × REFIN × (8190/8192)
…
+4.32 × REFIN × (1/8192)
0V
−4.32 × REFIN × (1/8192)
…
−4.32 × REFIN × (8190/8192)
−4.32 × REFIN × (8191/8192)
Analog Output
±10 V Output Range
+4 × REFIN × (8191/8192)
+4 × REFIN × (8190/8192)
…
+4 × REFIN × (1/8192)
0V
−4 × REFIN × (1/8192)
…
−4 × REFIN × (8190/8192)
−4 × REFIN × (8191/8192)
±10.8 V Output Range
+4.32 × REFIN × (8191/8192)
+4.32 × REFIN × (8190/8192)
…
+4.32 × REFIN × (1/8192)
0V
−4.32 × REFIN × (1/8192)
…
−4.32 × REFIN × (8190/8192)
−4.32 × REFIN × (8191/8192)
Table 11. Bipolar Output, Twos Complement Coding
Digital Input
MSB
01
01
…
00
00
11
…
10
10
1111
1111
…
0000
0000
1111
…
0000
0000
1111
1111
…
0000
0000
1111
…
0000
0000
LSB
1111
1110
…
0001
0000
1111
…
0001
0000
±5 V Output Range
+2 × REFIN × (8191/8192)
+2 × REFIN × (8190/8192)
…
+2 × REFIN × (1/8192)
0V
−2 × REFIN × (1/8192)
…
−2 × REFIN × (8190/8192)
−2 × REFIN × (8191/8192)
Table 12. Unipolar Output, Straight Binary Coding
Digital Input
MSB
11
11
…
10
10
01
…
00
00
1111
1111
…
0000
0000
1111
…
0000
0000
1111
1111
…
0000
0000
1111
…
0000
0000
LSB
1111
1110
…
0001
0000
1111
…
0001
0000
+5 V Output Range
+2 × REFIN × (16,383/16,384)
+2 × REFIN × (16,382/16,384)
…
+2 × REFIN × (8193/16,384)
+2 × REFIN × (8192/16,384)
+2 × REFIN × (8191/16,384)
…
+2 × REFIN × (1/16,384)
0V
Analog Output
+10 V Output Range
+4 × REFIN × (16,383/16,384)
+4 × REFIN × (16,382/16,384)
…
+4 × REFIN × (8193/16,384)
+4 × REFIN × (8192/16,384)
+4 × REFIN × (8191/16,384)
…
+4 × REFIN × (1/16,384)
0V
Rev. D | Page 22 of 32
+10.8 V Output Range
+4.32 × REFIN × (16,383/16,384)
+4.32 × REFIN × (16,382/16,384)
…
+4.32 × REFIN × (8193/16,384)
+4.32 × REFIN × (8192/16,384)
+4.32 × REFIN × (8191/16,384)
…
+4.32 × REFIN × (1/16,384)
0V
AD5722/AD5732/AD5752
Ideal Output Voltage to Input Code Relationship—AD5722
Table 13. Bipolar Output, Offset Binary Coding
Digital Input
MSB
1111
1111
…
1000
1000
0111
…
0000
0000
1111
1111
…
0000
0000
1111
…
0000
0000
LSB
1111
1110
…
0001
0000
1111
…
0001
0000
±5 V Output Range
+2 × REFIN × (2047/2048)
+2 × REFIN × (2046/2048)
…
+2 × REFIN × (1/2048)
0V
−2 × REFIN × (1/2048)
…
−2 × REFIN × (2046/2048)
−2 × REFIN × (2047/2047)
Analog Output
±10 V Output Range
+4 × REFIN × (2047/2048)
+4 × REFIN × (2046/2048)
…
+4 × REFIN × (1/2048)
0V
−4 × REFIN × (1/2048)
…
−4 × REFIN × (2046/2048)
−4 × REFIN × (2047/2048)
±10.8 V Output Range
+4.32 × REFIN × (2047/2048)
+4.32 × REFIN × (2046/2048)
…
+4.32 × REFIN × (1/2048)
0V
−4.32 × REFIN × (1/2048)
…
−4.32 × REFIN × (2046/2048)
−4.32 × REFIN × (2047/2048)
Analog Output
±10 V Output Range
+4 × REFIN × (2047/2048)
+4 × REFIN × (2046/2048)
…
+4 × REFIN × (1/2048)
0V
−4 × REFIN × (1/2048)
…
−4 × REFIN × (2046/2048)
−4 × REFIN × (2047/2048)
±10.8 V Output Range
+4.32 × REFIN × (2047/2048)
+4.32 × REFIN × (2046/2048)
…
+4.32 × REFIN × (1/2048)
0V
−4.32 × REFIN × (1/2048)
…
−4.32 × REFIN × (2046/2048)
−4.32 × REFIN × (2047/2048)
Analog Output
+10 V Output Range
+4 × REFIN × (4095/4096)
+4 × REFIN × (4094/4096)
…
+4 × REFIN × (2049/4096)
+4 × REFIN × (2048/4096)
+4 × REFIN × (2047/4096)
…
+4 × REFIN × (1/4096)
0V
+10.8 V Output Range
+4.32 × REFIN × (4095/4096)
+4.32 × REFIN × (4094/4096)
…
+4.32 × REFIN × (2049/4096)
+4.32 × REFIN × (2048/4096)
+4.32 × REFIN × (2047/4096)
…
+4.32 × REFIN × (1/4096)
0V
Table 14. Bipolar Output, Twos Complement Coding
Digital Input
MSB
0111
0111
…
0000
0000
1111
…
1000
1000
1111
1111
…
0000
0000
1111
…
0000
0000
LSB
1111
1110
…
0001
0000
1111
…
0001
0000
±5 V Output Range
+2 × REFIN × (2047/2048)
+2 × REFIN × (2046/2048)
…
+2 × REFIN × (1/2048)
0V
−2 × REFIN × (1/2048)
…
−2 × REFIN × (2046/2048)
−2 × REFIN × (2047/2048)
Table 15. Unipolar Output, Straight Binary Coding
Digital Input
MSB
1111
1111
…
1000
1000
0111
…
0000
0000
1111
1111
…
0000
0000
1111
…
0000
0000
LSB
1111
1110
…
0001
0000
1111
…
0001
0000
+5 V Output Range
+2 × REFIN × (4095/4096)
+2 × REFIN × (4094/4096)
…
+2 × REFIN × (2049/4096)
+2 × REFIN × (2048/4096)
+2 × REFIN × (2047/4096)
…
+2 × REFIN × (1/4096)
0V
Rev. D | Page 23 of 32
AD5722/AD5732/AD5752
INPUT SHIFT REGISTER
The input shift register is 24 bits wide and consists of a read/write bit (R/W), a reserved bit (zero) that must always be set to 0, three
register select bits (REG0, REG1, REG2), three DAC address bits (A2, A1, A0), and 16 data bits (data). The register data is clocked in MSB
first on the SDIN pin. Table 16 shows the register format, and Table 17 describes the function of each bit in the register. All registers are
read/write registers.
Table 16. Input Register Format
MSB
DB23
R/W
DB22
Zero
DB21
REG2
DB20
REG1
DB19
REG0
DB18
A2
DB17
A1
DB16
A0
LSB
DB15 to DB0
Data
Table 17. Input Register Bit Functions
Bit Mnemonic
R/W
Description
Indicates a read from or a write to the addressed register.
REG2, REG1, REG0
Used in association with the address bits to determine if a write operation is to the DAC register, the output range
select register, the power control register, or the control register.
REG2
REG1
REG0
Function
0
0
0
DAC register
0
0
1
Output range select register
0
1
0
Power control register
0
1
1
Control register
These DAC address bits are used to decode the DAC channels.
A2
A1
A0
Channel Address
0
0
0
DAC A
0
1
0
DAC B
1
0
0
Both DACs
Data bits.
A2, A1, A0
Data
Rev. D | Page 24 of 32
AD5722/AD5732/AD5752
DAC REGISTER
The DAC register is addressed by setting the three REG bits to 000. The DAC address bits select the DAC channel in which the data
transfer is to take place (see Table 17). The data bits are in positions DB15 to DB0 for the AD5752 (see Table 18), DB15 to DB2 for the
AD5732 (see Table 19), and DB15 to DB4 for the AD5722 (see Table 20).
Table 18. Programming the AD5752 DAC Register
MSB
R/W
Zero
REG2
REG1
REG0
0
0
0
0
0
A2
A1
LSB
DB15 to DB0
A0
DAC address
16-bit DAC data
Table 19. Programming the AD5732 DAC Register
MSB
R/W
Zero
REG2
REG1
REG0
LSB
0
0
0
0
0
A2
A1
A0
DAC address
DB15 to DB2
DB1
DB0
14-bit DAC data
X
X
Table 20. Programming the AD5722 DAC Register
MSB
R/W
Zero
REG2
REG1
REG0
0
0
0
0
0
A2
A1
A0
DAC address
DB15 to DB4
DB3
DB2
DB1
LSB
DB0
12-bit DAC data
X
X
X
X
OUTPUT RANGE SELECT REGISTER
The output range select register is addressed by setting the three REG bits to 001. The DAC address bits select the DAC channel, and the
range bits (R2, R1, R0) select the required output range (see Table 21 and Table 22).
Table 21. Programming the Required Output Range
MSB
R/W
Zero
REG2
REG1
REG0
0
0
0
0
1
A2
A1
A0
DAC address
Table 22. Output Range Options
R2
0
0
0
0
1
1
R1
0
0
1
1
0
0
R0
0
1
0
1
0
1
Output Range (V)
+5
+10
+10.8
±5
±10
±10.8
Rev. D | Page 25 of 32
DB15 to DB3
DB2
DB1
LSB
DB0
Don’t care
R2
R1
R0
AD5722/AD5732/AD5752
CONTROL REGISTER
The control register is addressed by setting the three REG bits to 011. The value written to the address and data bits determines the
control function selected. The control register options are shown in Table 23 and Table 24.
Table 23. Programming the Control Register
MSB
R/W
Zero
REG2
REG1
REG0
A2
A1
A0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
1
1
0
0
0
0
0
1
0
1
DB15 to DB4
DB3
DB2
LSB
DB0
DB1
NOP, data = don’t care
TSD enable
Clamp enable
CLR select
Clear, data = don’t care
Load, data = don’t care
Don’t care
SDO disable
Table 24. Explanation of Control Register Options
Option
NOP
Clear
Load
SDO Disable
CLR Select
Clamp Enable
TSD Enable
Description
No operation instruction used in readback operations.
Addressing this function sets the DAC registers to the clear code and updates the outputs.
Addressing this function updates the DAC registers and, consequently, the DAC outputs.
Set by the user to disable the SDO output. Cleared by the user to enable the SDO output (default).
See Table 25 for a description of the CLR select operation.
Set by the user to enable the current-limit clamp. The channel does not power down upon detection of an overcurrent; the
current is clamped at 20 mA (default).
Cleared by the user to disable the current-limit clamp. The channel powers down upon detection of an overcurrent.
Set by the user to enable the thermal shutdown feature. Cleared by the user to disable the thermal shutdown feature (default).
Table 25. CLR Select Options
CLR Select Setting
0
1
Output CLR Value
Bipolar Output Range
0V
Negative full-scale
Unipolar Output Range
0V
Midscale
POWER CONTROL REGISTER
The power control register is addressed by setting the three REG bits to 010. This register allows the user to control and determine the
power and thermal status of the AD5722/AD5732/AD5752. The power control register options are shown in Table 26 and Table 27.
Table 26. Programming the Power Control Register
MSB
R/W
0
LSB
Zero
0
REG2
0
REG1
1
REG0
0
A2
0
A1
0
A0
0
DB15 to
DB11
X
DB10
0
DB9
OCB
DB8
X
DB7
OCA
DB6
X
DB5
TSD
DB4
X
DB3
X
DB2
PUB
DB1
X
DB0
PUA
Table 27. Power Control Register Functions
Option
PUA
PUB
TSD
OCA
OCB
Description
DAC A power-up. When set, this bit places DAC A in normal operating mode. When cleared, this bit places DAC A in power-down
mode (default). After setting this bit to power DAC A, a power-up time of 10 μs is required. During this power-up time, the DAC
register should not be loaded to the DAC output (see the Load DAC (LDAC) section). If the clamp enable bit of the control register
is cleared, DAC A powers down automatically on detection of an overcurrent, and PUA is cleared to reflect this.
DAC B power-up. When set, this bit places DAC B in normal operating mode. When cleared, this bit places DAC B in power-down
mode (default). After setting this bit to power DAC B, a power-up time of 10 μs is required. During this power-up time, the DAC
register should not be loaded to the DAC output (see the Load DAC (LDAC) section). If the clamp enable bit of the control register
is cleared, DAC B powers down automatically on detection of an overcurrent, and PUB is cleared to reflect this.
Thermal shutdown alert (read-only bit). In the event of an overtemperature situation, both DACs are powered down and this bit is set.
DAC A overcurrent alert (read-only bit). In the event of an overcurrent situation on DAC A, this bit is set.
DAC B overcurrent alert (read-only bit). In the event of an overcurrent situation on DAC B, this bit is set.
Rev. D | Page 26 of 32
AD5722/AD5732/AD5752
DESIGN FEATURES
ANALOG OUTPUT CONTROL
OVERCURRENT PROTECTION
In many industrial process control applications, it is vital that
the output voltage be controlled during power-up. When the
supply voltages change during power-up, the VOUTx pins are
clamped to 0 V via a low impedance path (approximately 4 kΩ).
To prevent the output amplifiers from being shorted to 0 V
during this time, Transmission Gate G1 is also opened (see
Figure 42). These conditions are maintained until the power
supplies have stabilized and a valid word is written to a DAC
register. At this time, G2 opens and G1 closes.
Each DAC channel of the AD5722/AD5732/AD5752 incorporates
individual overcurrent protection. The user has two options for
the configuration of the overcurrent protection: constant current
clamp or automatic channel power-down. The configuration of
the overcurrent protection is selected via the clamp enable bit in
the control register.
VOLTAGE
MONITOR
AND
CONTROL
G1
Constant Current Clamp (Clamp Enable = 1)
If a short circuit occurs in this configuration, the current is
clamped at 20 mA. This event is signaled to the user by the
setting of the appropriate overcurrent (OCX) bit in the power
control register. Upon removal of the short-circuit fault, the
OCX bit is cleared.
Automatic Channel Power-Down (Clamp Enable = 0)
VOUTA
06467-010
G2
Figure 42. Analog Output Control Circuitry
POWER-DOWN MODE
Each DAC channel of the AD5722/AD5732/AD5752 can be
individually powered down. By default, all channels are in
power-down mode. The power status is controlled by the power
control register (see Table 26 and Table 27 for details). When a
channel is in power-down mode, its output pin is clamped to
ground through a resistance of approximately 4 kΩ, and the
output of the amplifier is disconnected from the output pin.
If a short circuit occurs in this configuration, the shorted channel
powers down and its output is clamped to ground via a resistance
of approximately 4 kΩ. At this time, the output of the amplifier
is disconnected from the output pin. The short-circuit event is
signaled to the user via the overcurrent (OCX) bits, and the
power-up (PUX) bits indicate which DACs have powered down.
After the fault is rectified, the channels can be powered up again
by setting the PUX bits.
THERMAL SHUTDOWN
The AD5722/AD5732/AD5752 incorporate a thermal shutdown
feature that automatically shuts down the device if the core
temperature exceeds approximately 150°C. The thermal shutdown
feature is disabled by default and can be enabled via the TSD
enable bit of the control register. In the event of a thermal
shutdown, the TSD bit of the power control register is set.
Rev. D | Page 27 of 32
AD5722/AD5732/AD5752
APPLICATIONS INFORMATION
+5 V/±5 V OPERATION
GALVANICALLY ISOLATED INTERFACE
When operating from a single +5 V supply or a dual ±5 V supply,
an output range of +5 V or ±5 V is not achievable because sufficient headroom for the output amplifier is not available. In this
situation, a reduced reference voltage can be used. For example,
a 2 V reference voltage produces an output range of +4 V or ±4 V,
and the 1 V of headroom is more than enough for full operation.
A standard value voltage reference of 2.048 V can be used to
produce output ranges of +4.096 V and ±4.096 V.
In many process control applications, it is necessary to provide
an isolation barrier between the controller and the unit being
controlled to protect and isolate the controlling circuitry from
any hazardous common-mode voltages that may occur. The
iCoupler® family of products from Analog Devices, Inc., provides
voltage isolation in excess of 2.5 kV. The serial loading structure
of the AD5722/AD5732/AD5752 makes them ideal for isolated
interfaces because the number of interface lines is kept to a
minimum. Figure 43 shows a 4-channel isolated interface to the
AD5722/AD5732/AD5752 using an ADuM1400. For further
information, visit http://www.analog.com/icouplers.
In any circuit where accuracy is important, careful consideration
of the power supply and ground return layout helps to ensure
the rated performance. The printed circuit board on which the
AD5722/AD5732/AD5752 are mounted should be designed so
that the analog and digital sections are separated and confined
to certain areas of the board. If the AD5722/AD5732/AD5752
are in a system where multiple devices require an AGND-toDGND connection, the connection should be made at one
point only. The star ground point should be established as close
as possible to the device.
The AD5722/AD5732/AD5752 should have ample supply bypassing of a 10 μF capacitor in parallel with a 0.1 μF capacitor on
each supply located as close to the package as possible, ideally
right up against the device. The 10 μF capacitor is the tantalum
bead type. The 0.1 μF capacitor should have low effective series
resistance (ESR) and low effective series inductance (ESI) such
as the common ceramic types, which provide a low impedance
path to ground at high frequencies to handle transient currents
due to internal logic switching.
The power supply lines of the AD5722/AD5732/AD5752 should
use as large a trace as possible to provide low impedance paths
and reduce the effects of glitches on the power supply line. Fast
switching signals, such as a data clock, should be shielded with
digital ground to avoid radiating noise to other parts of the
board, and they should never be run near the reference inputs.
A ground line routed between the SDIN and SCLK lines helps
reduce crosstalk between them (this is not required on a
multilayer board that has a separate ground plane, but separating
the lines does help). It is essential to minimize noise on the
REFIN line because any unwanted signals can couple through
to the DAC outputs.
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 on the board. A
microstrip technique is by far the best method, but it is not
always possible with a double-sided board. In this technique,
the component side of the board is dedicated to a ground plane,
and signal traces are placed on the solder side.
ADuM1400*
MICROCONTROLLER
SERIAL CLOCK OUT
SERIAL DATA OUT
SYNC OUT
CONTROL OUT
V IA
V IB
V IC
V ID
ENCODE
ENCODE
ENCODE
ENCODE
DECODE
DECODE
DECODE
DECODE
V OA
V OB
V OC
V OD
TO SCLK
TO SDIN
TO SYNC
TO LDAC
*ADDITIONAL PINS OMITTED FOR CLARITY.
06467-011
LAYOUT GUIDELINES
Figure 43. Isolated Interface
VOLTAGE REFERENCE SELECTION
To achieve optimum performance from the AD5722/AD5732/
AD5752 over their full operating temperature range, a precision
voltage reference must be used. Thought should be given to the
selection of a precision voltage reference. The voltage applied to
the reference inputs is used to provide a buffered positive and
negative reference for the DAC cores. Therefore, any error in
the voltage reference is reflected in the outputs of the device.
There are four possible sources of error to consider when
choosing a voltage reference for high accuracy applications:
initial accuracy, temperature coefficient of the output voltage,
long-term drift, and output voltage noise.
•
•
•
Rev. D | Page 28 of 32
Initial accuracy error on the output voltage of an external
reference can lead to a full-scale error in the DAC. To
minimize these errors, a reference with low initial accuracy
error specification is preferred. Choosing a reference with
an output trim adjustment, such as the ADR421, allows a
system designer to trim out system errors by setting the
reference voltage to a voltage other than the nominal. The
trim adjustment can also be used to trim out temperatureinduced errors.
The temperature coefficient of a reference output voltage
affects INL, DNL, and TUE. A reference with a tight
temperature coefficient specification should be chosen to
reduce the dependence of the DAC output voltage on
ambient conditions.
Long-term drift is a measure of how much the reference
output voltage drifts over time. A reference with a tight
AD5722/AD5732/AD5752
•
long-term drift specification ensures that the overall
solution remains relatively stable over its entire lifetime.
Reference output voltage noise needs to be considered in
high accuracy applications that have relatively low noise
budgets. It is important to choose a reference with as low
an output noise voltage as practical for the required system
resolution. Precision voltage references such as the ADR431
(XFET® design) produce low output noise in the 0.1 Hz to
10 Hz range. However, as the circuit bandwidth increases,
filtering the output of the reference may be required to
minimize the output noise.
For all interfaces, the DAC output update can be initiated
automatically when all the data is clocked in, or it can be
performed under the control of LDAC. The contents of the
registers can be read using the readback function.
AD5722/AD5732/AD5752 to Blackfin® DSP Interface
Figure 44 shows how the AD5722/AD5732/AD5752 can be
interfaced to the Analog Devices Blackfin DSP. The Blackfin has
an integrated SPI port that can be connected directly to the SPI
pins of the AD5722/AD5732/AD5752 and the programmable I/O
pins that can be used to set the state of a digital input such as
the LDAC pin.
MICROPROCESSOR INTERFACING
Microprocessor interfacing to the AD5722/AD5732/AD5752 is
via a serial bus that uses a standard protocol compatible with
microcontrollers and DSP processors. The communications
channel is a 3-wire (minimum) interface consisting of a clock
signal, a data signal, and a synchronization signal. The AD5722/
AD5732/AD5752 require a 24-bit data-word with data valid on
the falling edge of SCLK.
SPISELx
SYNC
SCK
MOSI
SCLK
SDIN
ADSP-BF531
LDAC
06467-012
PF10
AD5722/
AD5732/
AD5752
Figure 44. AD5722/AD5732/AD5752 to Blackfin Interface
Table 28. Some Precision References Recommended for Use with the AD5722/AD5732/AD5752
Part No.
ADR431
ADR421
ADR03
ADR291
AD780
Initial Accuracy (mV max)
±1
±1
±2.5
±2
±1
Long-Term Drift (ppm typ)
40
50
50
50
20
Temp Drift (ppm/°C max)
3
3
3
8
3
Rev. D | Page 29 of 32
0.1 Hz to 10 Hz Noise (μV p-p typ)
3.5
1.75
6
8
4
AD5722/AD5732/AD5752
OUTLINE DIMENSIONS
5.02
5.00
4.95
7.90
7.80
7.70
24
13
4.50
4.40
4.30
3.25
3.20
3.15
EXPOSED
PAD
(Pins Up)
6.40 BSC
12
BOTTOM VIEW
TOP VIEW
1.05
1.00
0.80
1.20 MAX
0.15
0.05
SEATING
PLANE
0.10 COPLANARITY
0.65
BSC
8°
0°
0.20
0.09
0.30
0.19
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
0.75
0.60
0.45
061708-A
1
COMPLIANT TO JEDEC STANDARDS MO-153-ADT
Figure 45. 24-Lead Thin Shrink Small Outline Package, Exposed Pad [TSSOP_EP]
(RE-24)
Dimensions shown in millimeters
ORDERING GUIDE
Model 1
AD5722AREZ
AD5722AREZ-REEL7
AD5732AREZ
AD5732AREZ-REEL7
AD5752AREZ
AD5752AREZ-REEL7
1
Resolution (Bits)
12
12
14
14
16
16
Temperature Range
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
INL
±1 LSB
±1 LSB
±4 LSB
±4 LSB
±16 LSB
±16 LSB
Z = RoHS Compliant Part.
Rev. D | Page 30 of 32
TUE (% FSR)
±0.3
±0.3
±0.3
±0.3
±0.3
±0.3
Package Description
24-Lead TSSOP_EP
24-Lead TSSOP_EP
24-Lead TSSOP_EP
24-Lead TSSOP_EP
24-Lead TSSOP_EP
24-Lead TSSOP_EP
Package Option
RE-24
RE-24
RE-24
RE-24
RE-24
RE-24
AD5722/AD5732/AD5752
NOTES
Rev. D | Page 31 of 32
AD5722/AD5732/AD5752
NOTES
©2008–2011 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D06467-0-7/11(D)
Rev. D | Page 32 of 32
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