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FOD2741A, FOD2741B, FOD2741C Rev. 1.0.1

August 2008

FOD2741A, FOD2741B, FOD2741C

Optically Isolated Error Amplifier

Features

single package

CSA approval 1296837

VDE approval 40002463

BSI approval 8702, 8703

FOD2741B: tolerance 1%

FOD2741C: tolerance 2%

Applications

Description

The FOD2741 Optically Isolated Amplifier consists of the

popular KA431 precision programmable shunt reference

and an optocoupler. The optocoupler is a gallium ars-

enide (GaAs) light emitting diode optically coupled to a

silicon phototransistor. It comes in 3 grades of reference

voltage tolerance = 2%, 1%, and 0.5%.

The Current Transfer Ratio (CTR) ranges from 100% to

200%. It also has an outstanding temperature coefficient

of 50 ppm/°C. It is primarily intended for use as the error

amplifier/reference voltage/optocoupler function in iso-

lated AC to DC power supplies and DC/DC converters.

When using the FOD2741, power supply designers can

reduce the component count and save space in tightly

packaged designs. The tight tolerance reference elimi-

nates the need for adjustments in many applications.

The device comes in a 8-pin dip white package.

Functional Bock Diagram

Package Outlines

8

8

1

8

1

1

1

2

3

4

5

6

7

8 LED

FB

COMP

GND

NC

C

E

NC