x

x

x

x

x

x

B

LMV641

LMV641

STANDOFF DISTANCE

U1

U2

20 k:

BRIDGE TEMPCO COMPENSATION NETWORK

V

+

-

+

G = 23.2

BW-3 dB = 431 kHz

580:

1%

24.5 k:

1%

24.5 k:

1%

568 k:

1%

HONEYWELL

HMC1051Z

or EQUIVALENT

CONDUCTOR TO BE

CURRENT MEASURED

I(AC or DC)

FROM mAs TO 20A

V

+

20 k:

5 k:

0.1 PF

9V

ALKALINE

BATTERY

V

+

VOUT

V

+

RTH

RA

RB

-

+

TO ADC or

METER

CIRCUITRY

OFFSET TRIM

Copyright © 2016, Texas Instruments Incorporated

0

50

100

150

200

Time (us)

Vout (1V/div)

Vin (10mV/div)

C001

18

LMV641

SNOSAW3D – SEPTEMBER 2007 – REVISED AUGUST 2016

www.ti.com

Product Folder Links: LMV641

Submit Documentation Feedback

Copyright © 2007–2016, Texas Instruments Incorporated

Typical Applications (continued)

8.2.1.3 Application Curve

Figure 40. High Gain Inverting Amplifier Results

8.2.2 Anisotropic Magnetoresistive Sensor

Figure 41. A Battery-Operated System for Contact-Less Current Sensing Using an Anisotropic

Magnetoresistive Sensor

8.2.2.1 Design Requirements

The low operating current of the LMV641 makes it a good choice for battery-operated applications. Figure 41

shows two LMV641s in a portable application with a magnetic field sensor. The LMV641s condition the output

from an anisotropic magnetoresistive (AMR) sensor. The sensor is arranged in the form of a Wheatstone bridge.

This type of sensor can be used to accurately measure the current (either DC or AC) flowing in a wire by

measuring the magnetic flux density, B, emanating from the wire.