Integrated Single Supply Broadband Modem Mixed Signal Front End (MxFE®)

The AD9975 is an integrated single supply broadband modem mixed signal front end (MxFE) IC similar to the AD9875. Like the AD9875, this device contains a transmit path Interpolation Filter, and DAC along with a receive path that includes a PGA, LPF and ADC as required for a variety of broadband modem applications. Also on-chip is a PLL clock multiplier, which provides all required clocks from a single crystal or clock input.

Where the AD9975 and AD9875 differ is in the digital interface. The AD9975 has a digital interface that uses a single 10-bit data bus that is shared between the Tx and Rx paths. The AD9875 also includes a 10-bit data bus, but uses 5-bit interleaved nibbles for both the Tx and Rx paths, providing full duplex operation.

The AD9975 digital transmit and receive ports have individual TX/RX clocks and TX/RX enable lines. This interface connects directly to Homelug 1.0 PHY/MAC chips including the INT5130 from Intellon and CX11647 from Conexant. The AD9975 is available in a space-saving 48-lead LQFP package and is specified over the commercial (-40ºC to +85ºC) temperature range.

* Low Cost 3.3 V-CMOS Mixed Signal Front End Converter for Broadband

Modems * Compatile with the INT5130 and Conexant CX11647 HomePlug processor

ICs * 10-Bit D/A Converter (TxDAC+®) * 50 MSPS Input Word Rate * 2x Interpolating Low Pass Transmit Filter * 100 MSPS DAC Output Update Rate