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Description

The AD9774 is a single supply, oversampling, 14-bit digital-to analog converter (DAC) optimized for waveform reconstruction applications requiring exceptional dynamic range. Manufactured on an advanced CMOS process, it integrates a complete, low distortion 14-bit DAC with a 4×digital interpolation filter and clock multiplier. The two-stage, 4×digital interpolation filter provides more than a six-fold reduction in the complexity of the analog reconstruction-filter. It does so by multiplying the input data rate by a factor of four while simultaneously suppressing the original inband images by more than 69 dB. The on-chip clock multiplier provides all the necessary clocks. The AD9774 can reconstruct full-scale waveforms having bandwidths as high as 13.5 MHz when operating at an input data rate of 32 MSPS and a DAC output rate of 128 MSPS. The 14-bit DAC provides differential current outputs to support differential or single-ended applications. A segmented current source architecture is combined with a proprietary switching technique to reduce spurious components and enhance dynamic performance. Matching between the two current outputs ensures enhanced dynamic performance in a differential output configuration. The differential current outputs may be fed into a transformer or tied directly to an output resistor to provide two complementary, single-ended voltage outputs. A differential op amp topology can
also be used to obtain a single-ended output voltage. The output voltage compliance range is nominally 1.25 V.

Features

1. Single 3 V or 5 V Supply
2. 14-Bit DAC Resolution and Input Data Width
3. 32 MSPS Input Data Rate at 5 V
4. 13.5 MHz Reconstruction Bandwidth
4. 12 ENOBS @ 1 MHz
5. 77 dBc SFDR @ 5 MHz
6. 84% Passband to Nyquist Ratio
7. Internal 43Clock Multiplier
8. On-Chip 1.20 V Reference

Applications :

1. Communication Transmit Channel:
2. Wireless Basestations
3. ADSL/HFC Modems
4. Direct Digital Synthesis (DDS)