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
1 pA Monolithic Electrometer Operational Amplifier AD546* CONNECTION DIAGRAM 8-Pin Plastic Mini-DIP Package
AC PERFORMANCE 3 V/s Slew Rate 1 MHz Unity Gain Bandwidth Low Input Voltage Noise: 4 V 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
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.
1. The input bias current of the AD546 is specified, 100% tested and guaranteed with the device in the fully warmed-up condition.
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.
3. The AD546 is packaged in a standard, low cost, 8-pin mini-DIP.
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 AD546 is pin compatible with standard op amps; its plastic mini-DIP package is ideal for use with automatic insertion equipment.
2. The input offset voltage of the AD546 is laser trimmed to less than 1 mV (AD546K).
4. A low quiescent supply current of 700 µA minimizes any thermal effects which might degrade input bias current and input offset voltage specifications.
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. *Covered by Patent No. 4,639,683.
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