FOD2741A_08 Datasheet, PDF (1/15 Pages) Fairchild Semiconductor – Optically Isolated Error Amplifier

August 2008
FOD2741A, FOD2741B, FOD2741C
Optically Isolated Error Amplifier
Features
■ Optocoupler, precision reference and error amplifier in
single package
■ 2.5V reference
■ CTR 100% to 200%
■ 5,000V RMS isolation
■ UL approved E90700, Volume 2
CSA approval 1296837
VDE approval 40002463
BSI approval 8702, 8703
■ Low temperature coefficient 50ppm/°C max.
■ FOD2741A: tolerance 0.5%
FOD2741B: tolerance 1%
FOD2741C: tolerance 2%
Applications
■ Power supplies regulation
■ DC to DC converters
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
NC 1
C2
E3
NC ₄
8 LED
7 FB
6 COMP
5 ^GND
Package Outlines
8
1
8
1
8
1
©2004 Fairchild Semiconductor Corporation
FOD2741A, FOD2741B, FOD2741C Rev. 1.0.1
www.fairchildsemi.com