Dual, 14-Bit, 1230 MSPS, TxDAC+ Digital-to-Analog Converter

The AD9121 is a dual, 14-bit, high dynamic range digital-to-analog converter (DAC) that provides a sample rate of 1230 MSPS, permitting multicarrier generation up to the Nyquist frequency.

The AD9121 TxDAC+® includes features optimized for direct conversion transmit 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 F-MOD series from Analog Devices, Inc. A 4-wire serial port interface provides for programming/readback of many internal parameters. Full-scale output current can be programmed over a range of 8.7 mA to 31.7 mA. The AD9121 comes in a 72-lead LFCSP.

Product Highlights

* Ultralow noise and intermodulation distortion (IMD) enable high quality synthesis of wideband signals from baseband to high intermediate frequencies (IF).

* Proprietary DAC output switching technique enhances dynamic performance.

* Current outputs are easily configured for various single-ended or differential circuit topologies.

* Flexible LVDS digital interface allows the standard 28-wire bus to be reduced to one-half of the width.

Applications

* Wireless infrastructure

* W-CDMA, CDMA2000, TD-SCDMA, WiMAX, GSM, LTE

* Digital high or low IF synthesis

* Transmit diversity

* Wideband communications: LMDS/MMDS, point-to-point

* Flexible LVDS interface allows word or byte load

* Single-carrier W-CDMA ACLR = 82 dBc at 122.88 MHz IF

* Analog output: adjustable 8.7 mA to 31.7 mA, RL = 25 Ω to 50 Ω

* Integrated 2×/4×/8× interpolator/complex modulator allows carrier placement anywhere in the DAC bandwidth