LMP8481MM-SSLASHNOPB datasheet(19/29 Pages) TI1

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LMP8480, LMP8481

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SNVS829C – MARCH 1999 – REVISED SEPTEMBER 2015

Typical Applications (continued)

It should be noted that the minimum “zero” reading will be limited by the lower output swing and input offset. The

LMP8480 is functionally identical to the LMP8481, but with the VREFA and VREFB nodes grounded internally. The

LMP8481 can replace the LMP8480 if both the VREF inputs (pins 6 and 7) are grounded.

9.2.1.3 Application Curve

Figure 28. Unidirectional Transfer Function for Gain-of-20 Option

9.2.2 Bidirectional Current Sensing Using LMP8481

Figure 29. Bidirectional Current Sensing Using LMP8481

9.2.2.1 Design Requirements

Bidirectional operation is required where the measured load current can be positive or negative. Because VSENSE

can be positive or negative, and the output cannot swing negative, the “zero” output level must be level-shifted

above ground to a known zero reference point. The LMP8481 allows for the setting this reference point.

9.2.2.2 Detailed Design Procedure

The VREFA and VREFB pins set the zero reference point. The output “zero” reference point is set by applying a

voltage to the REFA and/or REFB pins. See the Unidirectional Application With LMP8480 section. VREFA and

VREFB Pins (LMP8481 Only) shows the output transfer function with a 1.2-V reference applied to the Gain-of-20

option.

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LMP8481MM-S/NOPB Datasheet(PDF) 19 Page - Texas Instruments