AM79D2251

Intelligent Access™ Voice Solutions www.DataSheet4U.com Am79D2251 Dual Intelligent Subscriber Line Audio-Processing Circuit (ISLAC) DISTINCTIVE CHARACTERISTICS s High performance digital signal processor provides programmable control of all major linecard functions — 32 and 24 kb/s ADPCM to G726, as well as A-law/µ-law and linear codec — Transmit and receive gain — Two-wire AC impedance — Transhybrid balance — Equalization — DC loop feeding — Smooth or abrupt polarity reversal — Loop supervision — Off-hook debounce circuit — Ground-key and ring-trip filters — Ringing generation and control — Adaptive hybrid balance — Line and circuit testing — Tone generation — Metering generation at 12 kHz and 16 kHz — Envelope shaping and level control s Selectable PCM/MPI or GCI digital interfaces — Supports most available master clock frequencies from 512 kHz to 8.196 MHz s 0 to 70°C commercial operation — –40°C to 85°C extended temperature range available s +3.3 V DC operation s Exceeds LSSGR and ITU requirements s Supports external ringing with on-chip ring-trip circuit — Automatic or manual ring-trip modes s DTMF detection according to Q.24 s 2100 Hz modem tone detection according to V.25 BLOCK DIAGRAM A1 ISLIC 7 4 LD1 VREF VCCA VCCD DGND1 B1 RC Networks and Protection A2 7 3 AGND1 DGND2 AGND2 TSCA/G P1-P3 ISLIC LD2 DRA/DD DXA/DU DCLK/S0 PCLK/FS B2 RREF Dual ISLAC 5 Ring-Trip Sense Resistors 5 MCLK RSHB BATH RSLB FS/DCL CS/RST DIO/S1 BATL RSPB BATP INT Pub. # 22829...