Datasheet
AD5306/AD5316/AD5326
Rev. F | Page 20 of 24
APPLICATIONS
TYPICAL APPLICATION CIRCUIT
The AD5306/AD5316/AD5326 can be used with a wide range
of reference voltages where the devices offer full one-quadrant
multiplying capability over a reference range of 0 V to V
DD
.
More typically, these devices are used with a fixed precision-
reference voltage. Suitable references for 5 V operation are the
AD780 and REF192 (2.5 V references). For 2.5 V operation, a
suitable external reference is the AD589, a 1.23 V band gap
reference.
Figure 36 shows a typical setup for the AD5306/
AD5316/AD5326 when using an external reference. Note that
A0 and A1 can be high or low.
AD5306/
AD5316/
AD5326
GND
SDA
SERIAL
INTERFACE
V
OUT
EXT
REF
0.1μF
V
REF
A
V
REF
C
V
REF
D
V
REF
B
AD780/REF192
WITH V
DD
= 5V
OR AD599 WITH
V
DD
= 2.5V
V
DD
= 2.5V TO 5.5V
V
IN
A0 A1
10μF
1μF
SCL
V
OUT
A
V
OUT
C
V
OUT
B
V
OUT
D
02066-036
Figure 36. AD5306/AD5316/AD5326
Using a 2.5 V External Reference
DRIVING V
DD
FROM THE REFERENCE VOLTAGE
If an output range of 0 V to V
DD
is required when the reference
inputs are configured as unbuffered, the simplest solution is to
connect the reference inputs to V
DD
. Because this supply may be
noisy and somewhat inaccurate, the AD5306/AD5316/AD5326
may be powered from the reference voltage, for example, using
a 5 V reference such as the REF195. The REF195 outputs a
steady supply voltage for the AD5306/AD5316/AD5326. The
typical current required from the REF195 is 500 μA supply
current and approximately 112 μA to supply the reference
inputs, if unbuffered. This is with no load on the DAC outputs.
When the DAC outputs are loaded, the REF195 also needs to
supply the current to the loads. The total current required (with
a 10 kΩ load on each output) is
612 μA + (5 V/10 kΩ) = 2.6 mA
The load regulation of the REF195 is typically 2 ppm/mA,
which results in an error of 5.2 ppm (26 μV) for the 2.6 mA
current drawn from it. This corresponds to a 0.0013 LSB error
at eight bits and a 0.021 LSB error at 12 bits.
BIPOLAR OPERATION USING THE
AD5306/AD5316/AD5326
The AD5306/AD5316/AD5326 are designed for single-supply
operation, but a bipolar output range is also possible using the
circuit in
Figure 37. This circuit gives an output voltage range
of ±5 V. Rail-to-rail operation at the amplifier output is
achievable using an AD820 or an OP295 as the output amplifier.
+5V
–5V
AD820/
OP295
10μF
6V TO 12V
0.1μF
R1
10kΩ
±5V
R2
10kΩ
A1
A0
G
ND
V
OUT
AD1585
+5V
2-WIRE
SERIAL
INTERFACE
SC
L
SD
A
GND
1
μ
F
AD5306/
AD5316/
AD5326
V
REF
A
V
REF
C
V
REF
D
V
REF
B
V
OUT
C
V
OUT
B
V
OUT
A
V
OUT
D
V
IN
V
DD
03756-A-037
Figure 37. Bipolar Operation with the AD5306/AD5316/AD5326
The output voltage for any input code can be calculated as follows:
(
)
()
()
12
2
R/RREFIN
R1
R2R1
N
/DREFIN
OUT
V ×−
+××
=
⎥
⎥
⎦
⎤
⎢
⎢
⎣
⎡
where:
D is the decimal equivalent of the code loaded to the DAC.
N is the DAC resolution.
REFIN is the reference voltage input.
With REFIN = 5 V, R1 = R2 = 10 kΩ,
V
OUT
= (10 × D/2
N
) − 5 V
MULTIPLE DEVICES ON ONE BUS
Figure 38 shows four AD5306 devices on the same serial bus.
Each has a different slave address since the states of the A0 and
A1 pins are different. This allows each of 16 DACs to be written
to or read from independently.
02066-038
PULL-UP
RESISTORS
SCL
SDA
AD5306
AD5306
SCL
SDA
A0
A1
V
DD
V
DD
V
DD
MASTER
A0
A1
SCL
SDA
AD5306
AD5306
SCL
SDA
A0
A1
A0
A1
Figure 38. Multiple AD5306 Devices on One Bus