AD8212:  High Voltage Current Shunt Monitor

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 in the data sheet).

The AD8212 features a patented output base current compensation 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.

Applications

Data Sheet, Rev. A, 11/07