x

x

x

x

x

x

B

LMV641

LMV641

STANDOFF DISTANCE

U1

U2

20 k:

BRIDGE TEMPCO COMPENSATION NETWORK

V

+

-

+

G = 23.2

580:

1%

24.5 k:

1%

24.5 k:

1%

568 k:

1%

HONEYWELL

HMC1051Z

or EQUIVALENT

CONDUCTOR TO BE

CURRENT MEASURED

FROM mAs TO 20A

V

+

20 k:

5 k:

0.1 PF

9V

ALKALINE

BATTERY

V

+

V

+

-

+

TO ADC or

METER

CIRCUITRY

OFFSET TRIM

LMV641

www.ti.com

SNOSAW3C – SEPTEMBER 2007 – REVISED FEBRUARY 2013

Compensation by External Resistor

In some applications it is essential to drive a capacitive load without sacrificing bandwidth. In such a case, in the

placed in series between the load capacitance and the output. This introduces a zero in the circuit transfer

function, which counteracts the effect of the pole formed by the load capacitance, and ensures stability. The

Values ranging from 5

system with less ringing and overshoot, but will also limit the output swing and the short circuit current of the

circuit.

Figure 42. Compensation by Isolation Resistor

TYPICAL APPLICATIONS

ANISOTROPIC MAGNETORESISTIVE SENSOR

The low operating current of the LMV641 makes it a good choice for battery operated applications. Figure 43

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.

Figure 43. A Battery Operated System for Contact-Less Current Sensing Using an Anisotropic

Magnetoresistive Sensor

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