GENERAL DESCRIPTION

The AD9877 is a single-supply set-top box and cable modem mixed-signal front end. The device contains a transmit path interpolation filter, complete quadrature digital upconverter, and transmit DAC. The receive path contains a 12-bit ADC and dual 8-bit ADCs. All internally required clocks and an output system clock are generated by the phase-locked loop (PLL) from a single crystal or clock input.

FEATURES

Low cost 3.3 V CMOS MxFE™ for

MCNS-DOCSIS-, DVB-, DAVIC-compliant

set-top box and cable modem applications

232 MHz quadrature digital upconverter

12-bit direct IF DAC (TxDAC+®)

Up to 65 MHz carrier frequency DDS

Programmable sampling clock rates

Selectable interpolation filter

Analog Tx output level adjust

12-bit, 33 MSPS direct IF ADC

Dual 8-bit, 16.5 MSPS sampling IQ ADCs

Two 12-bit Σ-Δ auxiliary DACs

Direct interface to AD8321/AD8325 or

AD8322/AD8327 PGA cable driver

APPLICATIONS

Cable modems

Set-top boxes

Wireless modems