MAX4194–MAX4197

Micropower, Single-Supply,

Rail-to-Rail, Precision

Instrumentation Amplifiers

Maxim Integrated | 12

www.maximintegrated.com

Power-Supply Bypassing and Layout

Good layout technique optimizes performance by

decreasing the amount of stray capacitance at the

instrumentation amplifier’s gain-setting pins. Excess

capacitance will produce peaking in the amplifier’s fre-

quency response. To decrease stray capacitance, min-

imize trace lengths by placing external components as

close to the instrumentation amplifier as possible. For

best performance, bypass each power supply to

ground with a separate 0.1µF capacitor.

Transducer Applications

The MAX4194–MAX4197 instrumentation amplifiers can

be used in various signal-conditioning circuits for ther-

mocouples, PT100s, strain gauges (displacement sen-

sors), piezoresistive transducers (PRTs), flow sensors,

and bioelectrical applications. Figure 7 shows a simpli-

fied example of how to attach four strain gauges (two

identical two-element strain gauges) to the inputs of the

MAX4194. The bridge contains four resistors, two of

which increase and two of which decrease by the same

ratio.

With a fully balanced bridge, points A (IN+) and B (IN-)

impedance (120Ω to 350Ω) of the strain gauges, how-

ever, could cause significant voltage drop contributions

by the wires leading to the bridge, which would cause

culated as follows:

tation amplifier.

errors may occur.

Figure 7. Strain Gauge Connection to the MAX4194

IN-

R

R

R

R

IN+

RG+

RG-

OUT

REFERENCE

μP

REF

B

A

MAX144

ADC

R = 120

Ω - 350Ω

Chip Information

TRANSISTOR COUNT: 432

Package Information

For the latest package outline information and land patterns (foot-

prints), go to www.maximintegrated.com/packages. Note that a

“+”, “#”, or “-” in the package code indicates RoHS status only.

Package drawings may show a different suffix character, but the

drawing pertains to the package regardless of RoHS status.

PACKAGE

TYPE

PACKAGE

CODE

OUTLINE

NO.

LAND

PATTERN NO.

8 SO

S8-5

21-0041

90-0096