OPA388IDBVT datasheet(21/50 Pages) TI2

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8 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification, and

TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining

suitability of components for their purposes. Customers should validate and test their design

implementation to confirm system functionality.

8.1 Application Information

The OPAx388 is a unity-gain stable, precision operational amplifier family free from unexpected output and

phase reversal. The use of proprietary zero-drift circuitry gives the benefit of low input offset voltage over time

and temperature, as well as lowering the 1/f noise component. As a result of the high PSRR, these devices

work well in applications that run directly from battery power without regulation. The OPAx388 family is optimized

for full rail-to-rail input, allowing for low-voltage, single-supply operation or split-supply use. These miniature,

high-precision, low-noise amplifiers offer high-impedance inputs that have a common-mode range 100 mV

beyond the supplies without input crossover distortion and a rail-to-rail output that swings within 5 mV of the

supplies under normal test conditions. The OPAx388 series of precision amplifiers is designed for upstream

analog signal chain applications in low or high gains, as well as downstream signal chain functions such as DAC

buffering.

8.2 Typical Applications

8.2.1 Bidirectional Current-Sensing

This single-supply, low-side, bidirectional current-sensing solution detects load currents from –1 A to +1 A. The

single-ended output spans from 110 mV to 3.19 V. This design uses the OPAx388 because of its low offset

voltage and rail-to-rail input and output. One of the amplifiers is configured as a difference amplifier and the other

amplifier provides the reference voltage.

Figure 8-1 shows the solution.

LOAD

BUS

OUT

REF

SHUNT

U1A

U1B

SHUNT

Figure 8-1. Bidirectional Current-Sensing Schematic

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OPA388, OPA2388, OPA4388

SBOS777D – NOVEMBER 2016 – REVISED JULY 2020

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OPA388IDBVT Datasheet(PDF) 21 Page - Texas Instruments