The AD97421 is a 12-bit resolution， wideband， third generation member of the TxDAC series of high performance， low power CMOS digital-to-analog converters （DACs）。 The TxDAC family， consisting of pin-compatible 8-， 10-， 12-， and 14-bit DACs， is specifically optimized for the transmit signal path of communication systems. All of the devices share the same interface options， small outline package， and pinout， providing an upward or downward component selection path based on performance， resolution， and cost. The AD9742 offers exceptional ac and dc performance while supporting update rates up to 210 MSPS. The AD9742’s low power dissipation makes it well suited for portable and low power applications. Its power dissipation can be further reduced to a mere 60 mW with a slight degradation in performance by lowering the full-scale current output. Also， a power-down mode reduces the standby power dissipation to approximately 15 mW. A segmented current source architecture is combined with a proprietary switching technique to reduce spurious components and enhance dynamic performance. Edge-triggered input latches and a 1.2 V temperature compensated band gap reference have been integrated to provide a complete monolithic DAC solution. The digital inputs support 3 V CMOS logic families