AD5320BRM Analog Devices Inc, AD5320BRM Datasheet - Page 15

• Manufacturer Part Number: AD5320BRM
• Description: D/A Converter (D-A) IC
• Manufacturer: Analog Devices Inc

Specifications of AD5320BRM

• Resolution (bits): 12bit
• Digital Ic Case Style: MSOP
• No. Of Pins: 8
• Operating Temperature Range: -40°C To +105°C
• Update Rate: 0.125MSPS
• Mounting Type: Surface Mount
• Peak Reflow Compatible (260 C): No
• Rohs Status: RoHS non-compliant
• Settling Time: 8µs
• Number Of Bits: 12
• Data Interface: DSP, MICROWIRE™, QSPI™, Serial, SPI™
• Number Of Converters: 1
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 105°C
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power Dissipation (max): -
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIONS
USING REF19X AS A POWER SUPPLY FOR AD5320
Because the supply current required by the AD5320 is
extremely low, an alternative option is to use a REF19x voltage
reference (REF195 for 5 V or REF193 for 3 V) to supply the
required voltage to the part (see Figure 32). This is especially
useful if the power supply is noisy or if the system supply
voltages are at some value other than 5 V or 3 V (such as 15 V).
The REF19x outputs a steady supply voltage for the AD5320. If
the low dropout REF195 is used, the current it needs to supply
to the AD5320 is 140 μA. This is with no load on the output of
the DAC. When the DAC output is loaded, the REF195 also
needs to supply the current to the load. The total current
required (with a 5 kΩ load on the DAC output) is:
The load regulation of the REF195 is typically 2 ppm/mA,
which results in an error of 2.3 ppm (11.5 μV) for the 1.14 mA
current drawn from it. This corresponds to a 0.009 LSB error.
BIPOLAR OPERATION USING THE AD5320
The AD5320 is designed for single-supply operation but a bipolar
output range is also possible using the circuit in Figure 33. The
circuit below 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.
The output voltage for any input code can be calculated as
follows:
where D represents the input code in decimal (0 to 4095).
With V
This is an output voltage range of ±5 V with 000 hex
corresponding to a −5 V output and FFF hex corresponding to
a +5 V output.
140 μA + (5 V/5 kΩ) = 1.14 mA
V
V
O
O
DD
INTERFACE
=
=
= 5 V, R1 = R2 = 10 kΩ:
SERIAL
⎛
⎜
⎝
⎡
⎢
⎣
3-WIRE
V
10
Figure 32. REF195 as Power Supply to AD5320
4096
DD
×
×
D
⎛
⎜
⎝
15V
⎞
⎟
⎠
SYNC
SCLK
4096
−
DIN
D
REF195
5
V
⎞
⎟
⎠
×
⎛
⎜
⎝
R
1
AD5320
R
5V
+
1
R
140µA
2
⎞
⎟
⎠
−
V
V
OUT
DD
= 0V TO 5V
×
⎛
⎜
⎝
R
R
2
1
⎞
⎟
⎠
⎤
⎥
⎦
Rev. C | Page 15 of 20
+5V
USING AD5320 WITH AN OPTO-ISOLATED
INTERFACE
For 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 can occur in the area where the DAC is
functioning. Opto-isolators provide isolation in excess of 3 kV.
Because the AD5320 uses a 3-wire serial logic interface, it
requires only three opto-isolators to provide the required
isolation (see Figure 34). The power supply to the part also
needs to be isolated. This is done by using a transformer. On the
DAC side of the transformer, a 5 V regulator provides the 5 V
supply required for the AD5320.
SYNC
SCLK
DATA
10µF
POWER
0.1µF
Figure 34. AD5320 with An Opto-Isolated Interface
Figure 33. Bipolar Operation with the AD5320
3-WIRE SERIAL INTERFACE
V
DD
10kΩ
10kΩ
10kΩ
V
V
V
AD5320
REGULATOR
DD
DD
DD
5V
R1 = 10kΩ
SCLK
SYNC
DIN
V
OUT
AD5320
GND
V
DD
V
10µF
OUT
R2 = 10kΩ
AD820/
OP295
AD5320
+5V
–5V
0.1µF
±5V