Circuit Note
CN-0006
Circuit Designs Using Analog Devices Products
Apply these product pairings quickly and with confidence.
For more information and/or support call 1-800-AnalogD
(1-800-262-5643) or visit www.analog.com/circuit.
Devices Connected/Referenced
AD5764
Complete Quad, 16-Bit, High Accuracy DAC
ADR02
Precision 5.0 V Voltage Reference
High Accuracy, Bipolar Voltage Output Digital-to-Analog Conversion
Using the AD5764 DAC
CIRCUIT FUNCTION AND BENEFITS
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. Table 1 lists other 5 V
precision reference candidates from Analog Devices and their
respective attributes.
+15V –15V
10µF
10µF
100nF
100nF
100nF
BIN/2sCOMP
1
SYNC
SCLK
2
SCLK
SDIN
3
SDIN
SDO
4
SDO
REFAB
NC
REFCD
NC
AVSS
AVDD
REFGND
SYNC
BIN/2sCOMP
32 31 30 29 28 27 26 25
+5V
AGNDA 24
VOUTA 23
VOUTA
VOUTB 22
VOUTB
AGNDB 21
AD5764
5
CLR
AGNDC 20
LDAC
6
LDAC
VOUTC 19
VOUTC
D0
7
D0
VOUTD 18
VOUTD
D1
8
D1
AGNDD 17
10µF
ISCC
AVSS
PGND
10µF
AVDD
100nF
RSTIN
DVCC
10 11 12 13 14 15 16
DGND
9
RSTOUT
100nF
NC = NO CONNECT
10µF
+5V
+15V –15V
5303-064
A precision voltage reference must be used in order for the
DAC to achieve the optimum performance over its full
operating temperature range. The AD5764 incorporates
reference buffers, which eliminate the need for both a positive
and negative external reference and associated buffers. This
leads to further savings in both cost and board space. Because
the voltages applied to the reference inputs (REFAB, REFCD)
are used to generate the buffered positive and negative internal
references for the DAC cores, any error in the external voltage
reference is reflected in the outputs of the device.
4
100nF
The AD5764 is a high performance digital-to-analog converter
that offers guaranteed monotonicity, integral nonlinearity (INL)
of ±1 LSB (C-grade device), low noise, and 10 μs settling time.
Performance is guaranteed over wide operating supply voltage
ranges. The AVDD supply range is +11.4 V to +16.5 V, and the
AVSS operating range is from −11.4 V to −16.5 V. The nominal
full-scale output range is ±10 V.
VOUT 6
GND
RSTIN
CIRCUIT DESCRIPTION
ADR02
2 VIN
RSTOUT
This circuit provides high accuracy, bipolar data conversion
using the AD5764, a quad, 16-bit, serial input, bipolar voltage
output DAC. This circuit utilizes the ADR02 precision reference
to achieve optimal DAC performance over full operating
temperature range. The only external components needed for
this precision 16-bit DAC are a reference voltage source,
decoupling capacitors on the supply pins and reference inputs,
and an optional short-circuit current setting resistor leading to
savings in cost and board space. This circuit is well suited for
both closed-loop servo control and open-loop control
applications.
+15V
Figure 1. High Accuracy, Bipolar Configuration of the AD5764 DAC Using a
Precision Reference
In any circuit where accuracy is important, careful consideration of the power supply and ground return layout helps to
ensure the rated performance. The PCB on which the AD5764
is mounted must be designed so that the analog and digital
sections are physically separated and confined to certain areas
of the board. If the AD5764 is in a system where multiple
devices require an AGND-to-DGND connection, the connection is to be made at one point only. The star ground point is
established as close as possible to the device. The AD5764 must
have ample supply bypassing of 10 µF in parallel with 0.1 µF on
each supply, located as close to the package as possible, ideally
right up against the device. The 10 µF capacitors are the
Rev. A
“Circuits from the Lab” from Analog Devices have been designed and built by Analog Devices
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each circuit, and their function and performance have been tested and verified in a lab environment
at room temperature. However, you are solely responsible for testing the circuit and determining its
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Tel: 781.329.4700
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Fax: 781.461.3113
©2009 Analog Devices, Inc. All rights reserved.
CN-0006
Circuit Note
Table 1. Precision 5.0 V References
Part Number
Initial Accuracy Max
(mV)
Long-Term Drift Typ
(ppm)
Temp Drift Max
(ppm/°C)
0.1 Hz to 10 Hz Noise
Typ (µV p-p)
ADR435B
±2
40
3
8
ADR425B
±1
50
3
3.4
ADR02B
±3
50
3
10
ADR395B
±5
50
9
8
AD586T
±2.5
15
10
4
tantalum bead type. The 0.1 µF capacitor must have low
effective series resistance (ESR) and low effective series
inductance (ESL), 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 traces of the AD5764 must be as wide as
possible to provide low impedance paths and reduce the effects
of glitches on the power supply line. Fast switching signals, such
as clocks, must be shielded with digital ground to avoid
radiating noise to other parts of the board, and must never be
run near the reference inputs. A ground line routed between the
SDIN and SCLK lines helps reduce crosstalk between them (not
required on a multilayer board, which has a separate ground
plane; however, it is helpful to separate the lines). It is essential
to minimize noise on the reference inputs because it couples
through to the DAC output. Avoid crossover of digital and
analog signals. Traces on opposite sides of the board must run
at right angles to each other. This reduces the effects of
feedthrough on the board. A microstrip technique is
recommended, but not always possible with a double-sided
board. In this technique, the component side of the board is
dedicated to the ground plane, and signal traces are placed on
the solder side. Best layout and performance are achieved with
at least a 4-layer multilayer board, where there is a ground plane
layer, a power supply layer, and two signal layers.
LEARN MORE
Kester, Walt. 2005. The Data Conversion Handbook. Analog
Devices. Chapters 3 and 7.
MT-015 Tutorial, Basic DAC Architectures II: Binary DACs.
Analog Devices.
MT-031 Tutorial, Grounding Data Converters and Solving the
Mystery of AGND and DGND. Analog Devices.
MT-101 Tutorial, Decoupling Techniques. Analog Devices.
Voltage Reference Wizard Design Tool.
Data Sheets and Evaluation Boards
AD5764 Data Sheet.
AD5764 Evaluation Board.
ADR02 Data Sheet.
REVISION HISTORY
5/09—Rev. 0 to Rev. A
Updated Format .................................................................. Universal
10/08—Revision 0: Initial Version
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