AD546

a FEATURES DC PERFORMANCE 1 mV max Input Offset Voltage Low Offset Drift: 20 ␮V/؇ C 1 pA max Input Bias Current Input Bias Current Guaranteed Over Full Common-Mode Voltage Range AC PERFORMANCE 3 V/␮s Slew Rate 1 MHz Unity Gain Bandwidth Low Input Voltage Noise: 4 ␮V p-p, 0.1 Hz to 10 Hz Available in a Low Cost, 8-Pin Plastic Mini-DIP Standard Op Amp Pinout APPLICATIONS Electrometer Amplifiers Photodiode Preamps pH Electrode Buffers Log Ratio Amplifiers 1 pA Monolithic Electrometer Operational Amplifier AD546* CONNECTION DIAGRAM 8-Pin Plastic Mini-DIP Package PRODUCT DESCRIPTION PRODUCT HIGHLIGHTS 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 performance for such a low cost amplifier. Input bias currents are reduced significantly by using “topgate” JFET technology. The 1015 Ω 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 current 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...