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.

• 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 uA3680