The AD9873 integrates a complete 232 MHz quadrature digital transmitter and a multichannel receiver with four high-performance analog-to-digitalconverters (ADC) for various video and digital data signals. The AD9873 is designed for cable modem set-top box applications, where cost, size, power dissi-pation, and dynamic performance are critical attributes. A single external crystal is used to control all internal conversion and data processing cycles.
The transmit section of the AD9873 includes a high-speed direct digital synthesizer (DDS), a high-performance, high-speed 12-bit digital-to-analog converter (DAC), programmable clock multiplier circuitry, digital filters, and other digital signal processing functions, to form a complete quadrature digital up-converter device.On the receiver side, two 8-bit ADCs are optimized for IQ demodulated "out-of band" signals. An on-chip 10-bit ADC is typically used as a direct IF input of 256 QAM modulated signals in cable modem applications. A second direct IF input and an auxiliary video input with automatic programmable clamp
function are multiplexed to a high-performance 12-bit video ADC. The chip's programmable sigma-delta modulated outputs and an output clock may be used to control external components such as programmable gain amplifiers (PGA) and mixer stages. Three pins provide a direct interface to the AD8321/AD8323
programmable gain amplifier (PGA) cable driver.
The AD9873 is available in a space-saving 100-lead MQFP package.
Required Field 
