ADI 公司的AD9739A是高性能14位2.5 GSPS数模转换器（DAC），信号带宽从DC到3GHz，混合模式从1.25GHz到3GHz，双端口LVDS数据接口，可编输出电流从8.7mA到31.7mA，工作电压1.8V-3.3V，在2.5GSPS时的功耗为1.1W，主要用在宽带和通信系统，DOCSIS CMTS系统，军用干扰发射机，仪器和ATE，雷达和航天设备。本文介绍了AD9739A主要特性，产品亮点，功能方框图，和主处理器间推荐数字接口框图以及多种应用电路。
The AD9739A is a 14-bit, 2.5 GSPS high performance RF DAC capable of synthesizing wideband signals from dc up to 3 GHz. The AD9739A is pin and functionally compatible with the AD9739 with the exception that the AD9739A does not support synchronization and is specified to operate between 1.6 GSPS and 2.5 GSPS. By elimination of the synchronization circuitry, some nonideal artifacts such as imgs and discrete clock spurs remain stationary on the AD9739A between power-up cycles, thus allowing for possible system calibration. AC linearity and noise performance remain the same between the AD9739 and AD9739A.
The inclusion of on-chip controllers simplifies system integ-ration. A dual-port, source synchronous, LVDS interface simplifies the digital interface with existing FGPA/ASIC technology. On-chip controllers are used to manage external and internal clock domain variations over temperature to ensure reliable data transfer from the host to the DAC core. A serial peripheral interface (SPI) is used for device configuration as well as readback of status registers.
The AD9739A is manufactured on a 0.18 μm CMOS process and operates from 1.8 V and 3.3 V supplies. It is supplied in a 160-ball chip scale ball grid array for reduced package parasitics.
AD9739A产品亮点：
Ability to synthesize high quality wideband signals with bandwidths of up to 1.25 GHz in the first or second Nyquist zone.
A proprietary quad-switch DAC architecture provides exceptional ac linearity performance while enabling mix-mode operation.
A dual-port, double data rate, LVDS interface supports the maximum conversion rate of 2500 MSPS.
On-chip controllers manage external and internal clock domain skews.
Programmable differential current output with a 8.66 mA to 31.66 mA range.
AD9739A主要特性：
Direct RF synthesis at 2.5 GSPS update rate
DC to 1.25 GHz in baseband mode
1.25 GHz to 3.0 GHz in mix mode
Industry leading single/multicarrier IF or RF synthesis
Dual-port LVDS data interface
Up to 1.25 GSPS operation
Source synchronous DDR clocking
Pin-compatible with the AD9739
Programmable output current: 8.7 mA to 31.7 mA
Low power: 1.1 W at 2.5 GSPS
AD9739A应用：
Broadband communications systems
DOCSIS CMTS systems
Military jammers
Instrumentation, automatic test equipment
Radar, avionics
图1。AD9739A功能方框图
图2。AD9739A和主处理器间推荐数字接口框图
图3。AD9739A CLK输入和ADCLK914间接口框图
图4。AD9739A CLK输入和ADF4350 I间接口框图
图5。带宽高达2.2GHz的平衡/不平衡电路框图
图6。最低成本和尺寸的窄带RF工作电路框图
图7。采用TC1-1-43A+平衡/不平衡电路的扩展RF带宽的混合信号配置框图
