AD22055

REV. 0

–3–

ABSOLUTE MAXIMUM RATINGS

1

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . +3 V to +36 V

Peak Input Voltage (40 ms) . . . . . . . . . . . . . . . . . . . . . . . . 60 V

Reversed Continuous Supply Voltage . . . . . . . . . . . . . . –34 V

Operating Temperature . . . . . . . . . . . . . . . . –40

°C to +125°C

Storage Temperature . . . . . . . . . . . . . . . . . . –65

°C to +150°C

Output Short Circuit Duration . . . . . . . . . . . . . . . . Indefinite

Lead Temperature (Soldering, 60 sec) . . . . . . . . . . . . . +300

°C

permanent damage to the device. This is a stress rating only; the functional

operation of the device at these or any other conditions above those indicated in the

operation sections of this specification is not implied.

Exposure to absolute

maximum rating conditions for extended periods may affect device reliability.

ORDERING GUIDE

Temperature

Package

Package

Model

Range

Description

Option*

AD22055N

Plastic DIP

N-8

AD22055R

–40

°C to +125°C

Plastic SOIC

SO-8

*N = Plastic DIP; SO = Small Outline Package.

PIN CONNECTION

1

2

3

4

8

7

6

5

TOP VIEW

(Not to Scale)

AD22055

IN–

OUT

OFS

IN+

GND

FILT

GAIN

PIN DESCRIPTION

8-Pin SOIC

Pin

Function

1

IN–

2

Ground

3

Filter

4

Gain

5

Out

7

OFS

8

IN+

PRODUCT DESCRIPTION

The AD22055 is a single supply difference amplifier consisting

of a precision balanced attenuator, a very low drift preamplifier

and an output buffer amplifier (A1 and A2, respectively, in the

functional block diagram). It has been designed so that small

without the use of any other active components.

The common-mode range resistors in this network are trimmed

to match better than one part in 10,000. The resistive attenua-

tor network is situated at the input to the AD22055 (Pins 1

and 8) allowing the common-mode voltage at Pins 1 and 8 to be

two times greater than that which can be tolerated by the actual

input of A1. As a result, the input common-mode range extends

from ground to the power supply voltage.

Two small filter capacitors (not shown) have been included at

the inputs to A1 to minimize the effects of any spurious RF sig-

nals present in the signal.

Internal feedback around A1 sets the closed-loop gain of the

preamplifier to 40 V/V from the input pins, and the output of

A1 is connected to Pin 3 via a 80 k

Ω resistor, which is trimmed

to

±3% to facilitate the low-pass filtering of the signal. The out-

put buffer A2 has a gain of 10 V/V (using a precise 1 k

Ω resistor

from Pin 4 to ground) setting the precalibrated, overall gain of

the AD22055, to 400 V/V. This gain is easily user-configurable.

Overall gain is programmed using the following equation:

Gain

= 40 1+

9 k

Ω









V/V

(1)

The dynamic properties of the AD22055 are optimized for

interfacing to transducers, particularly those with a Wheatstone

Bridge configuration. Its rejection of large, high frequency,

common-mode signals makes it superior to that of many alter-

native approaches. This is due to the very careful design of

the input attenuator and the integration of this highly balanced,

high impedance system with the preamplifier.

WARNING!

ESD SENSITIVE DEVICE

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily

accumulate on the human body and test equipment and can discharge without detection.

Although the AD22055 features proprietary ESD protection circuitry, permanent damage may

occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD

precautions are recommended to avoid performance degradation or loss of functionality.