GND

25 k

25 k

+

±

OPA388

GND

+5V

100 k

REF5025

+5V

+

±

OPA388

GND

+5V

R2

10 k

GND

100 k

+5V

G = 5 +

NŸ

+SENSE

-SENSE

Load Cell

OPA388

+

±

DAC8830

DGND

AGND

Serial Interface

RFB

INV

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21

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Copyright © 2016, Texas Instruments Incorporated

System Examples (continued)

8.3.2 Precision, Low-Noise, DAC Buffer

The OPA388 can be used for a precision DAC buffer, as shown in Figure 44, in conjunction with the DAC8830.

The OPA388 provides an ultra-low drift, precision output buffer for the DAC. A wide range of DAC codes can be

used in the linear region because the OPA388 employs zero-crossover technology. A precise reference is

essential for maximum accuracy because the DAC8830 is a 16-bit converter.

Figure 44. Precision DAC Buffer

8.3.3 Load Cell Measurement

Figure 45 shows the OPA388 in a high-CMRR dual-op amp instrumentation amplifier with a trim resistor and 6-

wire load cell for precision measurement. Figure 46 illustrates the output voltage as a function of load cell

resistance change, along with the nonlinearity of the system.

Figure 45. Load Cell Measurement Schematic