Ultralow Noise, High Speed, BiFET Op Amp AD745
FEATURES ULTRALOW NOISE PERFORMANCE 2.9 nV/͙Hz at 10 kHz 0.38 V p, 0.1 Hz to 10 Hz 6.9 fA/͙Hz Current Noise at 1 kHz
CONNECTION DIAGRAMS 8-Pin Plastic Mini-DIP (N) & 8-Pin Cerdip (Q) Packages
NC 1 OFFSET NULL 1
EXCELLENT AC PERFORMANCE 12.5 V/s Slew Rate 20 MHz Gain Bandwidth Product THD = 0.0002% @ 1 kHz Internally Compensated for Gains of +5 (or –4) or Greater
– IN 2
NC 4 +IN
–VS 6 NC
15 NC 14 NC
10 NC 9 NC
The AD745’s guaranteed, tested maximum input voltage noise of 4 nV/√Hz at 10 kHz is unsurpassed for a FET-input monolithic op amp, as is its maximum 1.0 µV p noise in a 0.1 Hz to 10 Hz bandwidth. The AD745 also has excellent dc performance with 250 pA maximum input bias current and 0.5 mV maximum offset voltage.
The AD745 is an ultralow noise, high speed, FET input operational amplifier. It offers both the ultralow voltage noise and high speed generally associated with bipolar input op amps and the very low input currents of FET input devices. Its 20 MHz bandwidth and 12.5 V/µs slew rate makes the AD745 an ideal amplifier for high speed applications demanding low noise and high dc precision. Furthermore, the AD745 does not exhibit an output phase reversal.
The internal compensation of the AD745 is optimized for higher gains, providing a much higher bandwidth and a faster slew rate. This makes the AD745 especially useful as a preamplifier where low level signals require an amplifier that provides both high amplification and wide bandwidth at these higher gains. The AD745 is available in five performance grades. The AD745J and AD745K are rated over the commercial temperature range of 0°C to +70°C. The AD745A and AD745B are rated over the industrial temperature range of –40°C to +85°C. The AD745S is rated over the military temperature range of –55°C to +125°C and is available processed to MIL-STD-883B, Rev. C. The AD745 is available in 8-pin plastic mini-DIP, 8-pin cerdip, 16-pin SOIC, or in chip form.
OP37 & RESISTOR (—)
AD745 & RESISTOR OR OP37 & RESISTOR
OPEN-LOOP GAIN – dB
AD745 + RESISTOR ( )
RESISTOR NOISE ONLY (– – –)
PHASE MARGIN – Degrees
INPUT NOISE VOLTAGE – nV/ Hz
OFFSET NULL – IN
APPLICATIONS Sonar Photodiode and IR Detector Amplifiers Accelerometers Low Noise Preamplifiers High Performance Audio
NC = NO CONNECT
EXCELLENT DC PERFORMANCE 0.5 mV max Offset Voltage 250 pA max Input Bias Current 2000 V/mV min Open Loop Gain Available in Tape and Reel in Accordance with EIA-481A Standard
16-Pin SOIC (R) Package
SOURCE RESISTANCE – Ω
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10k 100k 1M FREQUENCY – Hz
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