U3761MB

U3761MB Low Voltage Standard Telephone Circuit with 13 Memories Description TEMIC’s low voltage telephone circuit, U3761MB performs all the speech and line interface functions required in an electronic telephone set, the tone ringer, the pulse and DTMF dialing with redial, notice function, and 13 memories. Features Speech Circuit D Last number redial up to 32 digits D Three by 32 digits direct (one touch) memory D Ten by 16 digits indirect (two touch) memory D Notice function up to 32 digits D Standard low-cost crystal 3.57 MHz or ceramic resonator D Adjustable DC characteristic D Symmetrical input of microphone amplifier D Receiving amplifier for dynamic or piezo-electric earpieces D Automatic line loss compensation Dialer D DTMF / pulse switchable D Pulse dialling 66/33 or 60/40 or DTMF dialling selectable by pin Tone Ringer D 2 Tone ringer D Adjustable volume D RC oscillator D Adjustable threshold D Selectable flashing duration by key pad D Pause function Benefits D Low number of external components D High quality through one IC solution TELEFUNKEN Semiconductors Rev. A2, 23-Apr-97 1 (23) Preliminary Information U3761MB Block Diagram / Applications 2 (23) 5V1 Á 220 k 220 k 220 k HKS Tip 1m 5M 75V HKS 470 BC546 18 k 3k MPSA42 22 k 220 n 2n2 XT HKS Microphone – amplifier + Control function Mute control Sidetone amplifier 3n3 ST Pulse control logic Supply current regulator Control function AGC current generator D/A converter Receiver attenuation RECIN 2.2 m R...