Wideband, Fast Settling Op Amp
The AD840 is a member of the Analog Devices' family of wide bandwidth operational amplifiers. This high speed/high precision family includes, among others, the AD841, which is unity-gain stable, and the AD842, which is stable at a gain of two or greater and has 100 mA minimum output current drive. These devices are fabricated using Analog Devices' junction isolated complementary bipolar (CB) process. This process permits a combination of dc precision and wideband ac performance previously unobtainable in a monolithic op amp. In addition to its 400 MHz gain bandwidth product, the AD840 offers extremely fast settling characteristics, typically settling to within 0.01% of final value in 100 ns for a 10 volt step.
The AD840 remains stable over its full operating temperature range at closed-loop gains of 10 or greater. It also offers a low quiescent current of 12 mA maximum, a minimum output current drive capability of 50 mA, a low input voltage noise of 4 nV/(root)Hz and a low input offset voltage of 0.3 mV maximum (AD840K).
The 400 V/µs slew rate of the AD840, along with its 400 MHz gain bandwidth, ensures excellent performance in video and pulse amplifier applications. This amplifier is ideally suited for use in high frequency signal conditioning circuits and wide bandwidth active filters. The extremely rapid settling time of the AD840 makes it the preferred choice for data acquisition applications which require 12-bit accuracy. The AD840 is also appropriate for other applications such as high speed DAC and ADC buffer amplifiers and other wide bandwidth circuitry.