UTC MC34118 LINEAR INTEGRA
TED CIRCUIT UTC UNISONIC TECHNOLOGIES CO., LTD. 1 QW-R108-007,AVOICE SWITCHED SPEAKER-PHONE CIRCUIT DESCRIPTION The UTC MC34118 voice switched speaker-phone integrated circuit incorporates the necessary amplifiers, attenuators, level detectors and control algorithm to form the heart of a high quality hands-free speaker-phone system. It includes a microphone amplifier with adjustable gain and mute control. Transmit and Receive attenuators which operate in a complementary manner, level detectors at both input and output of both attenuators, and background noise monitors for both the transmit and receive channels. A dial tone detector prevents the dial tone from being attenuated by the receive background noise monitor circuit. Also two line driver amplifiers which can be used to form a hybrid network in conjunction with an external coupling transformer. A high-pass filter can be used to filter out 60Hz noise in the receive channel, or for other filtering functions. A chip disable pin permits powers down the entire circuit to converse power on long loops where loop current is at a minimum. The UTC MC34118 may be operated from a power supply, or it can be powered from the telephone line, requiring typically 5mA. The UTC MC34118 can be interfaced directly to TIP and RING( through a coupling transformer) for stand-alone operation, or it can be used in conjunction with a handset speech network and/or other features of a feature phone. FEATURES *Improved attenuator gain range: 52dB between Transmit and Receive *Low voltage operation for line-powered applications(3~6.5V) *4-point signal sensing for improved sensitivity *Background noise monitors for both Transmit and Receive paths DIP-28 SOP-28 *Microphone amplifier gain set by external Resistors-Mute function included *Chip disable for active/standby operation *On board filter pinned-out for user defined function *Dial tone detector to inhibit receive idle mode during dial tone presence ABSOLUTE MAXIMUM RATINGS(Ta=25°C,Voltages referred to pin 22) PARAMETER SYMBOL VALUE UNIT Supply Voltage Vcc -1~7 V Voltage at Pin 3 V3 -1~Vcc+1 V Voltage at Pin 12( mute) V12 -1~Vcc+1 V Voltage at Pin 13( VLC) V13 -1~Vcc+0.5 V Voltage at Pin 9, Pin 21, and Pin 2 V9, 21, 2 -0.5~Vcc+0.5 V Storage temperature Tstr -65~150 °C
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