TP3076 COMBO® II Programmable PCM CODEC/Filter for ISDN and Digital Phone Applications General Description The TP3076 is a second-generation combined PCM CODEC and Filter devices optimized for digital switching applications on subscriber line and trunk cards and digital phone applications. Using advanced switched capacitor techniques, COMBO II combines transmit bandpass and receive lowpass channel filters with a companding PCM encoder and decoder. The devices are A-law and μ-law selectable and employ a conventional serial PCM interface capable of being clocked up to 4.096 MHz. A number of programmable functions may be controlled via a serial control port. Channel gains are programmable over a 25.4 dB range in each direction. To enable COMBO II to interface to the SLIC control leads, a number of programmable latches are included; each may be configured as either an input or an output. The TP3076 provides 4 latches.