+IN

-IN

V

+

V

-

LMP8645

+

-

+

L

o

a

d

•

LMP8645, LMP8645HV

www.ti.com

SNOSB29G – NOVEMBER 2009 – REVISED SEPTEMBER 2015

7 Detailed Description

7.1 Overview

Operating from a 2.7-V to 12-V supply range, the LMP8645 accepts input signals with a common-mode voltage

range of –2 V to 42 V, while the LMP8645HV accepts input signals with a common-mode voltage range of –2 V

to 76 V. The LMP8645 and LMP8645HV have adjustable gain, set by a single resistor, for applications where

supply current and high common-mode voltage are the determining factors.

7.1.1 Theory of Operation

Figure 15. Current Monitor Example Circuit

voltage.

where

•

(1)

This current flows entirely in the external gain resistor developing a voltage drop equal to:

(2)

This voltage is buffered and presented at the output with a very low output impedance allowing a very easy

interface to other devices (ADC,

μC…).

where

•

(3)

Copyright © 2009–2015, Texas Instruments Incorporated

Submit Documentation Feedback

11

Product Folder Links: LMP8645 LMP8645HV