1 pA Monolithic Electrometer Operational Amplifier

The AD546 is a monolithic electrometer combining the virtues of low (1 pA) input bias current with the cost effectiveness of a plastic mini-DIP package. Both input offset voltage and input offset voltage drift are laser trimmed, providing very high perfor-mance for such a low cost amplifier.

Input bias currents are reduced significantly by using "topgate" JFET technology. The 1015 (ohm) common-mode impedance, resulting from a bootstrapped input stage, insures that input bias current is essentially independent of common-mode voltage variations.

The AD546 is suitable for applications requiring both minimal levels of input bias current and low input offset voltage.

Applications for the AD546 include use as a buffer amplifier for cur-rent output transducers such as photodiodes and pH probes. It may also be used as a precision integrator or as a low droop rate sample and hold amplifier. The AD546 is pin compatible with standard op amps; its plastic mini-DIP package is ideal for use with automatic insertion equipment.

The AD546 is available in two performance grades, all rated over the 0°C to +70°C commercial temperature range, and packaged in an 8-pin plastic mini-DIP.