AD645

a FEATURES Improved Replacement for Burr-Brown OPA-111 and OPA-121 Op Amp LOW NOISE 2 ␮V 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 Low Noise, Low Drift FET Op Amp AD645 8-Pin Plastic Mini-DIP (N) Package CONNECTION DIAGRAMS TO-99 (H) Package CASE OFFSET NULL –IN +IN –VS OFFSET NULL 8 1 7 HIGH DC ACCURACY 250 ␮V max Offset Voltage 1 ␮V/؇ 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 V O T PR RIF M I D ED 1 2 3 4 TOP VIEW 8 NC +V AD645 7 +VS – IN 6 OUTPUT 5 OFFSET NULL 3 + IN 2 6 OUTPUT AD645 4 –V 5 OFFSET NULL NC = NO CONNECT NOTE: CASE IS CONNECTED TO PIN 8 PRODUCT DESCRIPTION The AD645 is available in six performance grades. The AD645J and AD645K are rated over the commercial temperature range of 0°C to +70°C. The AD645A, AD645B, and the ultraprecision AD645C are rated over the industrial temperature range of –40°C to +85°C. The AD645S is rated over the military temperature range of –55°C to +125°C and is available processed to MIL-STD-883B. The AD645 is available in an 8-pin plastic mini-DIP, 8-pin header, or in die form. PRODUCT HIGHLIGHTS 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 in...