
Preliminary Technical Data
AD5062/AD5063
reference. The AD5062/AD5063 have just one reference input,
REFIN. The voltage on the reference input is used to supply the
positive input to the Dac . Therefore any error in the reference
will be reflected in the Dac.
There are 4 possible sources of error when choosing a voltage
reference for high accuracy applications; initial accuracy, ppm
drift, long term drift and output voltage noise. Initial accuracy
on the output voltage of the Dac will lead to a full scale error in
the Dac. To minimize these errors, a reference with high initial
accuracy is preferred. Also, choosing a reference with an output
trim adjustment, such as the ADR425 allow a system designer
to trim system errors out by setting a reference voltage to a
voltage other than the nominal. The trim adjustment can also
be used at temperature to trim out any error.
Rev. Pr B | Page 15 of 17
AD5062/3
THREE-WIRE
SERIAL
INTERFACE
SYNC
SCLK
DIN
5V
4.096V
V
OUT
= 0V TO 4.096V
ADR392
Figure 29. ADR392 as Reference to AD5062/AD5063
Long term drift is a measure of how much the reference drifts
over time. A reference with a tight long term drift specification
ensures that the overall solution remains relatively stable
during its entire lifetime.
The temperature co-efficient of a references output voltage
affect INL,DNL TUE. A reference with a tight temperature co-
efficient specification should be chosen to reduce temperatue
dependence of the Dac output voltage on ambient conditions.
In high accuracy applications, which have a relatively low
noise budget, reference output voltage noise needs to be
considered. Choosing a reference with as low an output noise
voltage as practical for the system noise resolution required is
important. Precision voltage references such as the ADR435
produce low output noise in the 0.1-10Hz region. Examples of
some recommended precision references for use as supply to
the AD5060 are shown in the figure below..
Part list of precision references for use with
AD5062/AD5063.
Part No.
Initial
Accuracy
(mV max)
ADR435
+/-6
3
ADR425
+/-6
3
ADR02
+/-5
3
ADR395
+/-6
25
Temp Drift
(ppm
o
C max)
0.1-10Hz Noise
(uV p-p typ)
3.4
3.4
15
5
Bipolar Operation Using the AD5062/AD5063
The AD5062/AD5063 has been designed for single-supply
operation but a bipolar output range is also possible using the
circuit in Figure 30. The circuit below will give an output
voltage range of ±4.096 V. Rail-to-rail operation at the
amplifier output is achievable using an AD820 or an OP295 as
the output amplifier.
The output voltage for any input code can be calculated as
follows:
V
O
=
V
DD
×
D
65536
×
R1
+
R2
R1
V
DD
×
R2
R1
where
D
represents the input code in decimal (0–16384).
With
VREF
= 5 V,
R
1 =
R
2 = 10 kW:
This is an output voltage range of ±5 V with 0000Hex
corresponding to a –5 V output and 3FFF Hex
corresponding to a +5 V output.
V
O
=
10
×
D
65536
5 V
AD5063
DacGND
V
DD
REF
OUT
SCLK
DIN
SYNC
+5V
+4.096V
EXTERNAL
OP AMP
BIPOLAR
OUTPUT
10
u
F
SERIAL
INTERFACE
0.1
u
F
0.1
u
F
INV
R
INV
+5V
–5V
R
FB
RFB
AGND
Figure 30. Bipolar Operation with the AD5063
Using AD5062/AD5063 with an Opto-Isolated
Interface Chip.
In process-control applications in industrial environments it is
often necessary to use an opto-isolated interface to protect and
isolate the controlling circuitry from any hazardous common-
mode voltages that may occur in the area where the DAC is
functioning. Because the AD5062/AD5063 uses a three-wire
serial logic interface, the ADuM130Xifamily s an ideal way to
provide digital isolation for the DAC interface.
The ADuM130x isolators provide three independent isolation
channels in a variety of channel configurations and data rates.
They operate across the full range from 2.7V to 5.5V, providing
compatibility with lower voltage systems as well as enabling a
voltage translation functionality across the isolation barrier.