REV. D

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a

Precision, 16 MHz

CBFET Op Amp

AD845

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 617/329-4700

Fax: 617/326-8703

CONNECTION DIAGRAMS

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-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-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

PRODUCT DESCRIPTION

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 preci-

sion, 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 con-

verters. The 250

µV max input offset voltage makes offset null-

ing 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.

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 oper-

ate 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.

Plastic Mini-DIP (N) Package

and Cerdip (Q) Package

16-Pin SOIC

(R-16) Package