Precision amplifier for bridge circuits

AM467

analog microelectronics

February 2011

Analog Microelectronics GmbH

Phone:

+49 (0)6131/91 073 – 0

8/9

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

Offset: 0 to ± 0.3 mV/V

Supply voltage: 5 V ± 10%

The following values are obtained for the above sensing element categories:

Fixed resistor R2 = 33 k; accuracy of 1%

Fixed resistor R4 = 12 k; accuracy of 1%

Measuring resistor R1 = 11 k; accuracy of 0.1%

Measuring resistor R3 = 120 k; accuracy of 0.1%

C1 = 1 nF to 5 nF (ceramic)

C2 = 100 pF (ceramic)

C3 = 100 nF (optional)

C4 = 470 pF optional (ceramic)

NOTES

For bridge circuits with characteristics other than the above (with other sensing element categories,

such as DMS sensing elements, for example) Analog Microelectronics can adapt the dimensioning

program on request. The proposed calibration is in principle usable for bridge configuration of >

0,5 kOhm.

An Excel program (Kali1_AM467_rev1.xls) is proposed for calibration (the calculation of the

definitive operating point). This is available on the www.analogmicro.de website.

A DLL (Dynamic Link Library) can be delivered on request. With help of this program the calibra-

tion Kali1_AM467 can be automated. The DLL allows a simple implementation of the calculation

procedure in a standardized program environment e.g. C

++, Labview, Visual Basis.

DIAGRAM and PINOUT

Figure 3: Diagram of AM467

1

8

2

7

3

6

4

5

OUT

IN-

IN+

GND

VCC

N.C.

N.C.

N.C.

Figure 4: AM467 Pinout

AM467

AMP

+

-

GND

4

1 OUT

8

VCC

IN+ 3

IN-

2

Output stage

with short

circuit proofing