PBL3726-18A

March 1996 PBL 3726/18A Universal Speech Circuit Description PBL 3726/18A is a standard version of the PBL 3726 family of the mask-programmable, monolithic integrated speech circuits for use in electronic telephones. It is designed for use with a low impedance microphone. Transmitting and receiving gain is regulated with line length. Different regulation for various current feeds can be set by external resistors. Typical current feeds as 48 V, 2 x 200 ohm, 48 V 2 x 400 ohm and 48 V 2 x 800 ohm can be handled. Application dependent parameters such as line balance, side tone level, amplification and frequency response are set by external components. Parameters are set independently which means easy adoption for various market needs. Key Features Minimum number of inexpensive external components, 7 capacitors and 11 resistors. Mute function for operation with DTMF-generator. Transmit and receive gain regulation for automatic loop loss compensation. Extended current and voltage range 5 - 130 mA, down to 2 V. Differential microphone input for good balance to ground. Balanced receiver output stage. Short start-up time. Stabilized DC-supply for low current CMOS diallers and/or electret microphones. 1 DTMF input 10 PBL 3726/18 AD AT AR DTMF-input controlled by mute. 17 12 13 DC 8 DC output for external CMOS device Mute (active low) 9 7 Sense Input 6 5 11 3 2 15 16 14 4 5 2 4 1 IC13(891176)A P Control output 3 B L 37 18-pin plastic DIP 20-...