OPA388IDBVT datasheet(21/45 Pages) TI1

21 / 45 page

ILOAD

VBUS

VOUT

VCC

VREF

VSHUNT

VCC

U1A

U1B

RSHUNT

OPA388, OPA2388, OPA4388

www.ti.com

SBOS777C – DECEMBER 2016 – REVISED MAY 2019

Product Folder Links: OPA388 OPA2388 OPA4388

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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 suitable 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 43 shows the solution.

Figure 43. Bidirectional Current-Sensing Schematic

OPA388IDBVT Datasheet(PDF) 21 Page - Texas Instruments