LC737212

Ordering number : EN5203203 CMOS LSI LC737212, LC737212M Telephone Dialer IC with On-Chip Memory for PushButton Telephones Overview The LC737212 and LC737212M are CMOS LSI telephone dialers for pushbutton telephones. They support both DTMF and pulse dialing. These products include 25 16-digit memories for storing telephone numbers and one 63-digit memory for redialing, and they provide, in a single chip, all the functions required for dialing and control for a standard independent telephone, including on-hook dialing and a hold function. They also provide a serial I/O interface for connection to a microcontroller. Functions Fabrication in a CMOS process that allows these circuits to be directly operated from a telephone line Support for single-contact keypads Built-in oscillator circuit (fosc = 3.58 MHz) that can drive either a standard color-TV crystal oscillator element or a ceramic resonator High-precision DTMF signal Frequency generator circuit (±0.1%) adopted for eased ceramic resonator selection Five one-touch 16-digit auto-dial memories and 20 quick-dialing memories On-hook or off-hook can be specified for memory entries. Mode change and pause data items can be stored in the dialing memories. 63-digit redial memory Automatic pause (3.9 seconds) insertion when the mode is switched. Automatic pause (1.0 second) insertion after a flash operation. Mode changing is one-directional, from pulse mode to tone mode. Output of a key press tone (1036...