MT8840

® ISO2-CMOS MT8840 Data Over Voice Modem Features Performs ASK (amplitude shift keyed) modulation and demodulation 32 kHz carrier frequency Up to 2 kbit/s full duplex data transfer rate On-chip oscillator On-chip tone caller for alerting functions Adjustable tone caller frequencies Selectable self-loop test mode 5V/2.5mA power supply ISO2 -CMOS and switched capacitor technologies 18 Pin DIP MT8840AE MT8840AS ISSUE 4 November 1990 Ordering Information 18 Pin Plastic DIP 18 Pin SOIC 0°C to +85°C Description The MT8840 is a carrier over voice modem which allows simultaneous transfer of voice and data over a single pair of wires. Data is transferred on an amplitude shift keyed (ASK) 32 kHz carrier. On-chip filters remove voice frequency signals from the received composite voice and data signal prior to demodulation. The modulating signal is a bit stream with a typical data rate of 2 kbit/s. In addition, the device contains a two tone warbler which functions as a telephone ringer. The device is fabricated in MITEL’s double-poly ISO2-CMOS technology utilizing switched-capacitor techniques. Applications Simultaneous data and voice communication in PABXs 2 kbit/s data modem "Smart" telephone sets OSC1 OSC2 CK32 ETC MTC FATC Timing and Control Tone Caller TCO TxDI Modulator TX Bandpass Filter TX PostFilter RxDO Demodulator AGC RX Bandpass Filter RX PreFilter R O U T I N G TxO RxE RxI DET CRx VDD VSS VRef LOOP Figure 1 - Functio...