High Voltage

Current Shunt Monitor

AD8212

Rev. 0

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FEATURES

Adjustable gain

High common-mode voltage range

7 V to 65 V typical

7 V to >500 V with external pass transistor

Current output

Integrated 5 V series regulator

8-lead MSOP package

APPLICATIONS

Current shunt measurement

Motor controls

DC-to-DC converters

Power supplies

Battery monitoring

Remote sensing

FUNCTIONAL BLOCK DIAGRAM

AD8212

V+

COM

BIAS

ALPHA

1

8

5

2

3

6

OUTPUT

CURRENT

COMPENSATION

BIAS

CIRCUIT

Figure 1.

GENERAL DESCRIPTION

The AD8212 is a high common-mode voltage, current shunt

monitor. It accurately amplifies a small differential input voltage

in the presence of large common-mode voltages up to 65 V

(>500 V with an external PNP transistor).

The AD8212 is ideal for current monitoring across a shunt

resistor in applications controlling loads, such as motors and

solenoids. The current output of the device is proportional to

the input differential voltage. The user can select an external

resistor to set the desired gain. The typical common-mode

voltage range of the AD8212 is 7 V to 65 V.

Another feature of the AD8212 is high voltage operation,

which is achieved by using an external high voltage breakdown

PNP transistor. In this configuration, the common-mode range

of the AD8212 is equal to the breakdown of the external PNP

transistor. Therefore, operation at several hundred volts is easily

achieved (see Figure 23).

The AD8212 features a patented output base current compensa-

tion circuit for high voltage operation mode. This ensures that

no base current is lost through the external transistor and

excellent output accuracy is maintained regardless of common-

mode voltage or temperature.