PBL38541

• Minimum number of external components, with two filtered DCsupplies, 7 capacitors and 11 resistors.
• Easy adaption to various market needs.
• Mute control input for operation with DTMF - generator.
• A separate signaling input for payphone and DTMF tones controlled by mute.
• Transmitter and receiver gain regulation for automatic loop loss compensation.
• Extended current and voltage range 4 - 130 mA, down to 2 .2V.
• Differential microphone input for good balance to ground.
• Balanced receiver output stage.
• One stabilized DC - supply for low current CMOS diallers and or electret microphones. One settable current limited supply with 6 mA max. current.
• Short start up time.
• Excellent RFI performance.
• 18 - pin DIP and 20 - pin SO packages.

PBL 38541 is a monolithic integrated speech transmission circuit for use in electronic telephones or in any other line interface application. High settable supply current for auxiliary functions, up to 6.0 mA (at high line currents). The circuit PBL38541 is designed to accomodate either a low impedance dynamic or an electret microphone. Microphone can be muted separately. Payphone signaling and DTMF dialling tones have a separate input that is controlled by a mute signal. A signal summing point is available at the transmitter input. An internally preset line length compensation can be adjusted with external resistors to fit into different current feed systems as for ex. 48 V, 2 x 200 ohms, 48 V, 2 x 400 ohms and 48 V, 2 x 800 ohms. The line length compensation ofPBL38541 can be shut off in either high or low gain mode. Application dependent parameters such as line balance, side tone level, transmitter and receiver gains and frequency responces of PBL38541 are set independently by external components which means an easy adaption to various market needs. The setting of the parameters if carried out in certain order will counteract the interaction between the settings. The circuit PBL38541 provides four different DC - supplies to feed microphones,diallers and other more current consuming functions like handsfree systems.