8/10/04
Page 1 of 17
© 2004 Fairchild Semiconductor Corporation
LVTTL/LVCMOS COMPATIBLE LOW INPUT
CURRENT HIGH GAIN SPLIT DARLINGTON
OPTOCOUPLERS
SINGLE CHANNEL: FOD070L FOD270L
DUAL CHANNEL: FOD073L
DESCRIPTION
The FOD070L, FOD270L and FOD073L optocouplers consist of an AlGaAs
LED optically coupled to a high gain split darlington photodetector. These
devices are specified to operate at a 3.3V supply voltage.
The split darlington configuration separating the input photodiode and the first
stage gain from the output transistor permits lower output saturation voltage
and higher speed operation than possible with conventional darlington
phototransistor optocoupler. In the dual channel device FOD073L, an inte-
grated emitter – base resistor provides superior stability over temperature.
The combination of a very low input current of 0.5 mA and a high current
transfer ratio of 2000% makes this family particularly useful for input interface
to MOS, CMOS, LSTTL and EIA RS232C, while output compatibility is
ensured to LVCMOS as well as high fan-out LVTTL requirements.
An internal noise shield provides exceptional common mode rejection of
10 kV/µs.
FEATURES
•Low power consumption
•Low input current - 0.5 mA
•Available in single channel 8-pin DIP (FOD270L), 8-pin SOIC (FOD070L)
and dual channel 8-pin SOIC
• High CTR-2000%
• High CMR-10 kV/µs
• Guaranteed performance over temperature 0°C to 70°C
•U.L. recognized (File # E90700)
•LVTTL/LVCMOS Compatible output
APPLICATIONS
• Digital logic ground isolation – LVTTL/LVCMOS
•Telephone ring detector
• EIA-RS-232C line receiver
• High common mode noise line receiver
• µP bus isolation
• Current loop receiver
TRUTH TABLE
LED
V
O
ON LOW
OFF HIGH
8
8
1
8
1
1
1
2
3
4 5
6
7
8
+
_
V
F
V
CC
V
B
V
O
GND
FOD070L / FOD270L
N/C
N/C
1
2
3
4 5
6
7
8
+
_
V
F1
V
CC
V
01
V
02
GND
FOD073L
V
F2
_
+
