资 源 简 介
The AD9761 is a complete dual-channel， high speed， 10-bit CMOS DAC. The AD9761 has been developed specifically for use in wide bandwidth communicaTIon applicaTIons （e.g.， spread spectrum） where digital I and Q informaTIon is being processed during transmit operaTIons. It integrates two 10-bit， 40 MSPS DACs， dual 2 interpolation filters， a voltage reference， and digital input interface circuitry. The AD9761 supports a 20 MSPS per channel input data rate that is then interpolated by 2 up to 40 MSPS before simultaneously updating each DAC. The interleaved I and Q input data stream is presented to the digital interface circuitry， which consists of I and Q latches as well as some additional control logic. The data is de-interleaved back into its original I and Q data. An on-chip state machine ensures the proper pairing of I and Q data. The data output from each latch is then processed by a 2 digital interpolation filter that eases the reconstruction filter requirements. The interpolated output of each filter serves as the input of their respective 10-bit DAC. The DACs utilize a segmented current source architecture combined with a proprietary switching technique to reduce glitch energy and to maximize dynamic accuracy. Each DAC provides differential current output， thus supporting single-ended or differential applications. Both DACs are simultaneously updated and provide a nominal full-scale current of 10 mA. Also， the full-scale currents between each DAC are matched to within 0.07 dB （i.e.， 0.75%）， thus eliminating the need for additional gain calibration circuitry.
