PRODUCT DESCRIPTION
The AD645 is a low noise, precision FET input op amp. It offers the pico amp level input currents of a FET input device coupled with offset drift and input voltage noise comparable to a high performance bipolar input amplifier.

FEATURES
    Improved Replacement for Burr-Brown
    OPA-111 and OPA-121 Op Amp

LOW NOISE
    2 μV p-p max, 0.1 Hz to 10 Hz
    10 nV/√Hz max at 10 kHz
    11 fA p-p Current Noise 0.1 Hz to 10 Hz

HIGH DC ACCURACY
    250 μV max Offset Voltage
    1 μV/°C max Drift
    1.5 pA max Input Bias Current
    114 dB Open-Loop Gain
    Available in Plastic Mini-DIP, 8-Pin Header Packages, or Chip Form

APPLICATIONS
    Low Noise Photodiode Preamps
    CT Scanners
    Precision I-V Converters