CONNECTION DIAGRAMS

REV. C

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a

Ultralow Noise

BiFET Op Amp

AD743

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

Tel: 617/329-4700

Fax: 617/326-8703

PRODUCT HIGHLIGHTS

1. The low offset voltage and low input offset voltage drift of

the AD743 coupled with its ultralow noise performance

mean that the AD743 can be used for upgrading many

applications now using bipolar amplifiers.

2. The combination of low voltage and low current noise make

the AD743 ideal for charge sensitive applications such as

accelerometers and hydrophones.

3. The low input offset voltage and low noise level of the

AD743 provide >140 dB dynamic range.

4. The typical 10 kHz noise level of 2.9 nV/

√Hz permits a three

op amp instrumentation amplifier, using three AD743s, to be

built which exhibits less than 4.2 nV/

√Hz noise at 10 kHz

and which has low input bias currents.

100

1k

10k

100k

1

10

100

1000

1M

10M

SOURCE RESISTANCE –

Ω

OP27 &

RESISTOR

AD743 + RESISTOR

RESISTOR NOISE ONLY

AD743 & RESISTOR

OR

OP27 & RESISTOR

O

E

(

)

(– – –)

( — )

Input Noise Voltage vs. Source Resistance

FEATURES

ULTRALOW NOISE PERFORMANCE

2.9 nV/

√Hz at 10 kHz

0.38

V p-p, 0.1 Hz to 10 Hz

6.9 fA/

√Hz Current Noise at 1 kHz

EXCELLENT DC PERFORMANCE

0.5 mV max Offset Voltage

250 pA max Input Bias Current

1000 V/mV min Open-Loop Gain

AC PERFORMANCE

2.8 V/ s Slew Rate

4.5 MHz Unity-Gain Bandwidth

THD = 0.0003% @ 1 kHz

Available in Tape and Reel in Accordance with

EIA-481A Standard

APPLICATIONS

Sonar Preamplifiers

High Dynamic Range Filters (>140 dB)

Photodiode and IR Detector Amplifiers

Accelerometers

PRODUCT DESCRIPTION

The AD743 is an ultralow noise precision, FET input,

monolithic operational amplifier. It offers a combination of the

ultralow voltage noise generally associated with bipolar input op

amps and the very low input current of a FET-input device.

Furthermore, the AD743 does not exhibit an output phase

reversal when the negative common-mode voltage limit is

exceeded.

The AD743’s guaranteed, maximum input voltage noise of

4.0 nV/

√Hz at 10 kHz is unsurpassed for a FET-input

monolithic op amp, as is the maximum 1.0

µV p-p, 0.1 Hz to

10 Hz noise. The AD743 also has excellent dc performance with

250 pA maximum input bias current and 0.5 mV maximum

offset voltage.

The AD743 is specifically designed for use as a preamp in

capacitive sensors, such as ceramic hydrophones. It is available

in five performance grades. The AD743J and AD743K are rated

over the commercial temperature range of 0

°C to +70°C. The

AD743A and AD743B are rated over the industrial temperature

range of –40

°C to +85°C. The AD743S is rated over the

military temperature range of –55

°C to +125°C and is available

processed to MIL-STD-883B, Rev. C.

The AD743 is available in 8-pin plastic mini-DIP, 8-pin cerdip,

16-pin SOIC, or in chip form.

AD743

8

TOP VIEW

1

2

3

7

6

8

5

4

OUT

NULL

NC

NULL

–IN

+IN

–V

S

NC = NO CONNECT

OFFSET

NULL

AD743

–IN

+IN

8

1

2

3

4

9

10

11

12

13

14

16

NC

NC

NC

OUTPUT

+V

S

NC

NC

15

8

7

6

5

NC

OFFSET

NULL

NC

NC

NC

NC = NO CONNECT

8-Pin Plastic Mini-DIP (N)

and

8-Pin Cerdip (Q) Packages

16-Pin SOIC (R) Package