Texas Instruments Low-Power, Rail-to-Rail Output, 16-Bit Serial Input DIGITAL-TO-ANALOG CONVERTER DAC8531EVM DAC8531EVM 데이터 시트

3-9

W7

2–3

Select 5 V for the positive rail supply of the op-amp if W12 is closed

W8

1–2

Negative rail of the op-amp tied to analog GND

W10

Open

Disconnect V

REF

 from negative input of op-amp

W11

Open

(see Note)

Disconnect R12 (see Note)

W12

Close

Supplies the constant 5 V to the positive rail of the op-amp if W7, pins 2 and 3,
are shorted together

W13

5–6

Buffered output of DAC is channeled to the output terminals

If there is a need to incrementally adjust the capacitive load output, replace R12 with a capacitor with the desired capaci-
tance value and close W11.

Although the DAC8531 has been designed for single-supply operation, the
bipolar output of operation is implemented using the circuit shown in
Figure 3–7. The output of the circuit is an output voltage range of 

±

V

REF

.

 The

rail-to-rail operation at the amplifier output is achievable using an OPA350 as
the output amplifier.

_

+

5 V

–5 V

OPA350

R2

10 k

Ω

R1

10 k

Ω

U11

V

FB

V

OUT

V

REF

Three-Wire

Serial Interface

0.1 

µ

F

10 

µ

F

V

REF

DAC8531

U12

±

5 V

The EVM requires an additional 

±

15-V power supply to provide the supply rails

for the OPA177 op-amp, U17. The 

±

15-V supply is provided through the J1

connector of the EVM. The 15 V is attached to J1-3 terminal and the –15 V is
attached to J1-1 terminal. The 

±

15-V supplies are referenced to J1-2 terminal.

The OPA177 op-amp is specifically used to generate the –5-V supply voltage
for the negative rail of the OPA350 op-amp circuit, U12.

The bipolar configuration is accomplished by following the correct jumper
settings according to Table 3–6.