a FEATURES Replaces Hybrid Amplifiers in Many Applications AC PERFORMANCE: Settles to 0.01% in 350 ns 100 V/s Slew Rate 12.8 MHz min Unity-Gain Bandwidth 1.75 MHz Full-Power Bandwidth at 20 V p DC PERFORMANCE: 0.25 mV max Input Offset Voltage 5 V/؇C max Offset Voltage Drift 0.5 nA Input Bias Current 250 V/mV min Open-Loop Gain 4 V p max Voltage Noise, 0.1 Hz to 10 Hz 94 dB min CMRR Available in Plastic Mini-DIP, Hermetic Cerdip and SOIC Packages. Also Available in Tape and Reel in Accordance with EIA-481A Standard
The AD845 is a fast, precise, N channel JFET input, monolithic operational amplifier. It is fabricated using Analog Devices’ complementary bipolar (CB) process. Advanced laser-wafer trimming technology enables the very low input offset voltage and offset voltage drift performance to be realized. This precision, when coupled with a slew rate of 100 V/µs, a stable unity-gain bandwidth of 16 MHz, and a settling time of 350 ns 0.01%—while driving a parallel load of 100 pF and 500 Ω— represents a combination of features unmatched by any FET input IC amplifier. The AD845 can easily be used to upgrade many existing designs which use BiFET or FET input hybrid amplifiers and, in some cases, those which use bipolar input op amps. The AD845 is ideal for use in applications such as active filters, high speed integrators, photo diode preamps, sample-and-hold amplifiers, log amplifiers, and in buffering A/D and D/A converters. The 250 µV max input offset voltage makes offset nulling unnecessary in many applications. The common-mode rejection ratio of 110 dB over a ± 10 V input voltage range represents exceptional performance for a JFET input high speed op amp. This, together with a minimum open-loop gain of 250 V/mV ensures that 12-bit performance is achieved, even in unity-gain buffer circuits.
Precision, 16 MHz CBFET Op Amp AD845 CONNECTION DIAGRAMS Plastic Mini-DIP (N) Package and Cerdip (Q) Package
16-Pin SOIC (R-16) Package
The AD845 conforms to the standard op amp pinout except that offset nulling is to V+. The AD845J and AD845K grade devices are available specified to operate over the commercial 0°C to +70°C temperature range. AD845A and AD845B devices are specified for operation over the –40°C to +85°C industrial temperature range. The AD845S is specified to operate over the full military temperature range of –55°C to +125°C. Both the industrial and military versions are available in 8-pin cerdip packages. The commercial version is available in an 8-pin plastic mini-DIP and 16-pin SOIC; “J” and “S” grade chips are also available. PRODUCT HIGHLIGHTS
1. The high slew rate, fast settling time, and dc precision of the AD845 make it ideal for high speed applications requiring 12-bit accuracy. 2. The performance of circuits using the LF400, HA2520/2/5, HA2620/2/5, 3550, OPA605, and LH0062 can be upgraded in most cases. 3. The AD845 is unity-gain stable and internally compensated. 4. The AD845 is specified while driving 100 pF/500 Ω loads.
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