Designed for –52-V Battery Operation
50-mA Output Current Capability
Input Compatible With TTL and CMOS
High Common-Mode Input Voltage Range
Very Low Input Current
Fail-Safe Disconnect Feature
Built-in Output Clamp Diode
Direct Replacement for National DS3680
and Fairchild mA3680

description
The DS3680 telephone relay driver is a monolithic
integrated circuit designed to interface –48-V
relay systems to TTL or other systems in
telephone applications. It is capable of sourcing
up to 50 mA from standard –52-V battery power.
To reduce the effects of noise and IR drop between
logic ground and battery ground, these drivers are
designed to operate with a common-mode input
range of ±20 V referenced to battery ground. The
common-mode input voltages for the four drivers
can be different, so a wide range of input elements
can be accommodated. The high-impedance
inputs are compatible with positive TTL and
CMOS levels or negative logic levels. A clamp
network is included in the driver outputs to limit
high-voltage transients generated by the relay coil
during switching. The complementary inputs
ensure that the driver output is off as a fail-safe
condition when either output is open.
The DS3680 is characterized for operation from
0°C to 70°C.