FOD2743A_08 Datasheet, PDF (1/16 Pages) Fairchild Semiconductor – Optically Isolated Error Amplifier

August 2008
FOD2743A, FOD2743B, FOD2743C
Optically Isolated Error Amplifier
Features
■ Optocoupler, precision reference and error amplifier in
a single package
■ 2.5V reference
■ CTR 50% to 100% at 1mA
■ 5,000V RMS isolation
■ UL approval E90700, Vol. 2
CSA approval 1296837
VDE approval pending
BSI approval pending
■ Low temperature coefficient 50ppm/°C max
■ FOD2743A: tolerance 0.5%
FOD2743B: tolerance 1%
FOD2743C: tolerance 2%
Applications
■ Power supplies regulation
■ DC to DC converters
Description
The FOD2743 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 50% to
100%. 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 FOD2743, 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 an 8-pin dip white package.
Functional Bock Diagram
LED 1
COMP 2
GND ³
FB 4
8 NC
7C
6E
5 NC
Package Outlines
8
1
8
1
8
1
©2004 Fairchild Semiconductor Corporation
FOD2743A, FOD2743B, FOD2743C Rev. 1.0.1
www.fairchildsemi.com