TP3076 COMBO® II Programmable PCM CODEC/Filter for ISDNand Digital Phone ApplicationsGeneral Des criptionThe TP3076 is a second-generation combined PCM CODECand Filter devices optimized for digital switching applicationson subscriber line and trunk cards and digital phone applications.Using advanced switched capacitor techniques,COMBO II combines transmit bandpass and receive lowpasschannel filters with a companding PCM encoder anddecoder. The devices are A-law and μ-law selectable andemploy a conventional serial PCM interface capable of beingclocked up to 4.096 MHz. A number of programmable functionsmay be controlled via a serial control port.Channel gains are programmable over a 25.4 dB range ineach direction.To enable COMBO II to interface to the SLIC control leads, anumber of programmable latches are included; each may beconfigured as either an input or an output. The TP3076provides 4 latches.