A no-trimming SLIC two-chip set with coin telephone signaling facilities

A subscriber line interface circuit (SLIC) two-chip set is presented. It eliminates off-chip function trimming and contains integrated coin telephone set facilities and BORSCHT functions. The set consists of: (a) the subscriber interface LSI, a 320-V dielectrically isolated bipolar LSI with on-chip thin-film resistors and double-layer metal; and (b) the subscriber processor LSI, a 1.6 μm CMOS LSI with oversampling A-D/D-A converters and a microprogrammable digital signal processor. The chip sizes are 5.5 mm×6.06 mm and 6.0 mm×5.7 mm, respectively. With the two-chip set, a SLIC for coin telephone set interface can be established without high-precision filter components or hybrid ICs with their function trimming