Monolithic high voltage gated diode crosspoint array IC
A new gated diode crosspoint integrated circuit has been developed for telephone switching system applications. Central to the design of this high voltage device has been the extensive use of numerical modeling techniques. Two-dimensional simulation of the individual dielectrically isolated components that comprise the switch array has led to an improvement in their electrical parameters together with size reduction for each of their geometries. Additional calculations dealing with the routing of interconnect metalization about the perimeter of components has indicated how such runners may encroach upon these elements without degrading their performance so that higher density circuitry could be assembled onto a chip. The resulting IC therefore realizes substantial advances over its predecessors, including: increased scale of integration (9 vs. 4 crosspoint pairs), more compact design (2.1 vs, 3.6mm2per crosspoint pair), higher OFF state minimum blocking voltage (600 vs. 530 volts), and reduced ON state incremental resistance (10 vs. 18 ohms).
High-voltage subscriber line interface LSIs
A high-voltage BORSHT LSI family for an all solid-state subscriber line interface circuit in a digital local switching system has been developed. The family consists of a 320 V dielectrically isolated RTLSI, a 60 V bipolar BSH-LSI, and a CMOS control LSI. Ringing, reverse, and network-test functions were implemented in the RT-LSI chip using a high-voltage current-controlled p-n-p-n-switch integration technology. Battery feed, supervision, and hybrid functions have been integrated into the BSH-LSI chip using a high-precision analog bipolar process technology. The CMOS logic LSI performs a digital interface function with the PCM highway, as well as a control function for the other LSIs. Using this BORSHT LSI family along with a codec, it has become possible to make a low-cost and small-size subscriber line interface circuit for central office use.
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.