Mixed-Signal Front End Targets Cable Modems

Designed for use in cable modems and set-top boxes, the AD9877 mixed-signal front end integrates a 232 MHz quadrature digital transmitter, TxDAC d/a converter, 12-bit direct IF a/d converter in the receive path, and two 8-bit converters. It provides IF sampling to 75 MHz and gain control in the transmit path of 0.5 dB steps from 0 dB to 7.5 dB.The device also includes dual auxiliary 12-bit, sigma-delta d/a converters and programmable sampling clock rates. Performance features are said to be the result of smart-partitioning technology, whereby the mixed-signal components are segregated from the large-scale digital processing. Pricing is set at $4.53 each/100,000. For further information, contact ANALOG DEVICES INC., Wilmington, MA. (800) 262-5643.