Precision amplifier for bridge circuits

AM467

analog microelectronics

February 2011

Analog Microelectronics GmbH

Phone:

+49 (0)6131/91 073 – 0

3/9

An der Fahrt 13, D – 55124 Mainz

Fax:

+49 (0)6131/91 073 – 30

Rev. 1.1

Internet: http://www.analogmicro.de

Email:

info@analogmicro.de

FEATURES

• Wide differential input voltage range

(

±5 mV FS...±100 mV FS)

• Low offset

• Low offset drift

• Low input noise

• High CMRR: > 120 dB

• Wide operating temperature range:

– 40 °C... +125 °C

• Adjustable span of output signal

• Adjustable offset of output signal

• Rail-to-rail output stage:

VOUT = 0.2 V ... VCC – 0.2 V

• Sink/source output

• Single ratiometric supply: V

CC = 5 V

• Integrated EMV protective functions

• Overvoltage protection 12 V

• Integrated ESD protective functions

• Short-circuit-proofing

• Small-scale design

• Low cost circuit

GENERAL DESCRIPTION

AM467 is a high-precision integrated amplifier

which has been developed as signal condition

circuit for small differential input voltages within

a range of a few millivolts (

±5 to ±100 mV FS).

The chief component of the IC is a highly

accurate, low-noise amplifier circuit which can

be adjusted to the sensing elements using an

external network of resistors. Offset and span of

the output signal are adjustable in the range of

0.2 to Vcc-0.2Volt.

The rail-to-rail output makes the IC suitable for

the amplification of DMS and piezoceramic

sensing elements and GMR measuring cells with

respect to the specific calibration network.

BLOCK DIAGRAM

Figure 1: Block diagram for AM467

AM467

Input-

amplifier

Biasing

Unit

Output

stage

Short circuit

protection

Current limitation

VCC

OUT

GND

1

4

8

IN+

3

IN- 2