A monolithic subscriber line interface

A MONOLITHIC subscriber line interface circuit (SLIC) for use in PABX or CO applications, recently fabricated with 80V dielectric isolation technology, will be described. The SLIC provides battery feed with power denial control and loop current limiting, overvoltage protection (with some external devices), ringing control, line supervision with offhook, ring trip and ground key detection and 214 wire conversion. In addition, an uncommitted opamp is included for external connection of a balance network.