High Voltage CMOS Amplifier Enables High Impedance Sensing with a Single IC

September 01, 2015 // By Jon Munson, Linear Technology
Accurately measuring voltages requires minimizing the impact of the instrument connection to the tested circuit. Typical digital voltmeters (DVMs) use 10M resistor networks to keep loading effects to an inconspicuous level, but even this can introduce significant error, particularly in higher voltage circuits that involve high resistances. The solution is to use high impedance amplifiers in an electrometer configuration, so only miniscule amplifier input current comes from the test node.
Linear Technology, LTC6090, CMOS Amplifier