AD9876中文资料Broadband Modem Mixed-Signal Front End数据手册ADI规格书

描述 Description

The AD9876 is a single-supply broadband modem mixed-signalfront end (MxFE) IC. The device contains a transmit pathinterpolation filter and DAC and a receive path PGA, LPF, andADC supporting a variety of broadband modem applications.Also on-chip is a PLL clock multiplier that provides all requiredclocks from a single crystal or clock input. The AD9876 provides12-bit converter performance on both the Tx and Rx path.

The TxDAC+ uses a selectable digital 2× or 4× interpolationlow-pass or band-pass filter to further oversample transmit dataand reduce the complexity of analog reconstruction filtering.The transmit path signal bandwidth can be as high as 26 MHzat an input data rate of 64 MSPS. The 12-bit DAC providesdifferential current outputs for optimum noise and distortionperformance. The DAC full-scale current can be adjusted from2 to 20 mA by a single resistor, providing 20 dB of additionalgain range.

The receive path consists of a PGA, LPF, and ADC. The PGA hasa gain range of –6 dB to +36 dB, programmable in 2 dB steps,adding 42 dB of dynamic range to the receive path. The receive path LPF cutoff frequency can be programmed to either 12 MHzor 26 MHz. The filter cutoff frequency can also be tuned orbypassed where filter requirements differ. The 12-bit ADC usesa multistage differential pipeline architecture to achieve excellentdynamic performance with low power consumption.

The AD9876 provides a voltage regulator controller (VRC) thatcan be used with an external power MOSFET transistor to forma cost-effective 1.3 V linear regulator.

The digital transmit and receive ports are each multiplexed to abus width of six bits and are clocked at a frequency of twice the12-bit word rate.

The AD9876 ADC and/or DAC can also be used at samplingrates as high as 64 MSPS in a 6-bit resolution nonmultiplexed mode.

The AD9876 is pin compatible with the 10-bit AD9875. Both areavailable in a space-saving 48-lead LQFP package. They are specified over the industrial (–40°C to +85°C) temperature range.

APPLICATIONS

• Powerline Networking

• Home Phone Networking

• xDSL

• Broadband Wireless

• Home RF

特性 Features

• Low Cost 3.3 V CMOS Mixed-Signal Front End (MxFE™)

• Converter for Broadband Modems

• 10-/12-Bit D/A Converter (TxDAC+®)
• 64/32 MSPS Input Word Rate

• 2x/4x Interpolating LPF or BPF Transmit Filter

• 128 MSPS DAC Output Update Rate

• Wide (26 MHz) Transmit Bandwidth

• Power-Down Mode