U3810BM

TELEFUNKEN Semiconductors U3810BM Multi Standard Feature Phone Integrated Circuit Description The U3810BM multi-standard feature phone circuit is designed to be used with a microcontroller using a 2-wire serial bus. It performs all speech and line interface functions required in an electronic telephone set: the ringing function with switching regulator and melody generator, the DTMF dialling, the loudhearing with antilarsen and antidistortion systems, a power supply, a clock and a reset for the microcontroller. Transmit, receive and loudhearing gains control / AGC range / DTMF frequencies, pre-emphasis and level / melody generator, and mutes are programmable through the serial bus. Block diagramm Speech circuit Serial bus Loudhearing LH and Tone ringing DTMF dialer Tone ringer MC with EEPROM 93 7600 e Figure 1 Applications D Feature phones D Answering machines D Fax machines Benefits D Complete system integration of analog signal processing and digital control circuitry D One IC for various PTT standards, e.g. programmable specification via mC D Only three low-cost transducers needed (instead of four) Rev. A1: 19.01.1996 1 (31) U3810BM Features D Slope of DC characteristics adjustable by an external resistor TELEFUNKEN Semiconductors D Loudhearing gain programmable in eight steps of 4 dB, using the serial bus, or linearly adjusted, using a potentiometer D Gain of transmit and receive amplifiers automatically adjusted by line length control D Anti-larsen s...