Small, Surface Mount Optocouplers for  Power Conversion

An optocoupler is used in power conversion circuits, along with a voltage reference, to provide isolated feedback from the transformer's secondary side to a device in the primary side for control purposes.

We offer a selection of phototransistor output, Gallium Arsenide (GaAs) input optocouplers with narrow current transfer ratio (CTR) ranges in four small, surface mount package configurations for portable and compact products.

The voltage reference is a critical component in this application, and Shunt Regulators provide both a reference voltage and an error signal that makes them suitable for control applications.  With a wide range of voltages (down to 1.24 V), low drift, and low output noise, the Fairchild family of adjustable precision Shunt Regulators make it easy to select the best choice for your design.

Fairchild also provides an integrated solution for isolated feedback circuits, providing the error amplifier, reference voltage and optocoupler in a single package.  The FOD2712 Optically Isolated Error Amplifier allows power supply designers to reduce parts count, saving both space and cost.

MOC205 -- 40 to 80% CTR @ I_F = 10 mA I_F
MOC206 -- 63 to 125% CTR @ I_F = 10 mA I_F
MOC207 -- 100 to 200% CTR @ I_F = 10 mA I_F

H11A817A -- 80 to 160% CTR @ I_F < 10 mA I_F
H11A817B -- 13 to 260% CTR @ I_F < 10 mA I_F
H11A817C -- 200 to 400% CTR @ I_F < 10 mA I_F
H11A817D -- 300 to 600% CTR @ I_F < 10 mA I_F

HMA121 -- 50 to 600% CTR @ I_F < 10 mA I_F
HMA121A -- 100 to 300% CTR @ I_F < 10 mA I_F
HMA121B -- 50 to 150% CTR @ I_F < 10 mA I_F
HMA121C -- 100 to 200% CTR @ I_F < 10 mA I_F
HMA124 -- 100 to 1200% CTR @ I_F < 10 mA I_F
HMA2701 -- 50 to 300% CTR @ I_F < 10 mA I_F

HMHA281 -- 50 to 600% CTR @ I_F < 10 mA I_F
HMHA2801 -- 80 to 600% CTR @ I_F < 10 mA I_F