DALLAS A new single-chip analog front end (AFE) from Texas Instruments Inc. combines a codec, line driver and receiver functions as well as the transmit and receive digital and analog filtering required to implement the G.992.1 and G.992.2 asymmetric digital subscriber line (ADSL) standards. The TLFD-600 saves board space and reduces component counts for makers of customer-premise modems.
Packed into the chip are analog-to-digital and digital-to-analog converters with 14-bit resolution, which reduce system noise and allow for higher data rates at longer loop reaches, according to TI. There is also an on-chip clock-divide circuit that reduces the number of clock sources needed in the system. And, while some AFE solutions require several power supplies, the TLFD600 requires two, at 3.3 volts and 12 V. A power-down mode conserves power when the system is not handling transmissions.
Ming Chiang, vice president for mixed-signal product development, said the TLFD600 supports both the International Telecommunications Union and American Networking Standards Institute full-rate discrete multitone and G.Lite ADSL standards. The device interfaces gluelessly to TI's TMS320C6000 and TMS-320C5400 digital signal processors (DSPs), as well as to other standard DSPs, Chiang said.
The device is sampling now. Volume production is planned for the fourth quarter of this year. The part is available in a 64-pin, thermally enhanced PowerPad thin quad flat pack, and is priced at $10.50 in quantities of 100,000.
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EETInfo No. 622