A CMOS SLIC with an automatic balancing hybrid

A CMOS subscriber line interface circuit (SLIC) that has an automatic balancing hybrid facility is presented. Some of the key system aspects of line interface circuits, such as the relation between zero-loss switching and an automatic balancing hybrid circuit, power dissipation in the line circuit, and foreign voltage protection are described first. Next, details of the SLIC LSI, which comprises a dial pulse detecting circuit and and automatic balancing hybrid circuit, are described. The LSI is implemented with CMOS switched capacitor technology and is mounted on a 20-in DIL.