GENERAL DESCRIPTION
The AD9776A/AD9778A/AD9779A are dual, 12-/14-/16-bit, high dynamic range digital-to-analog converters (DACs) that provide a sample rate of 1 GSPS, permitting a multicarrier generation up to the Nyquist frequency. They include features optimized for direct conversion transmission applications, including complex digital modulation and gain and offset compensation. The DAC outputs are optimized to interface seamlessly with analog quadrature modulators such as the ADL537x FMOD series from Analog Devices, Inc. A 3-wire interface provides for programming/readback of many internal parameters. Full-scale output current can be programmed over a range of 10 mA to 30 mA. The devices are manufactured on an advanced 0.18 μm CMOS process and operate on 1.8 V and 3.3 V supplies for a total power consumption of 1.0 W. They are enclosed in a 100-lead thin quad flat package (TQFP).

FEATURES
   Low power: 1.0 W @ 1 GSPS, 600 mW @ 500 MSPS,
      full operating conditions
   Single carrier W-CDMA ACLR = 80 dBc @ 80 MHz IF
   Analog output: adjustable 8.7 mA to 31.7 mA,
      RL = 25 Ω to 50 Ω
   Novel 2×, 4×, and 8× interpolator/coarse complex modulator
      allows carrier placement anywhere in DAC bandwidth
   Auxiliary DACs allow control of external VGA and offset control
   Multiple chip synchronization interface
   High performance, low noise PLL clock multiplier
   Digital inverse sinc filter
   100-lead, exposed paddle TQFP

APPLICATIONS
   Wireless infrastructure
      W-CDMA, CDMA2000, TD-SCDMA, WiMax, GSM, LTE
   Digital high or low IF synthesis
   Internal digital upconversion capability
   Transmit diversity
   Wideband communications: LMDS/MMDS, point-to-point