Analog Devices has introduced a 14-bit D/A converter that enables cable television and broadband operators to synthesize the entire cable spectrum up to 1 GHz into a single RF port, while consuming a maximum of 1.1 W of power.
The AD9739A 14-bit, 2.5-GSPS D/A converter’s wide bandwidth and dynamic range enables cable operators to increase the QAM (quadrature amplitude modulation) channel densities by 20 times over the densities found in today’s cable modems. Competing D/A converter solutions require an additional 28 LVDS (low-voltage differential signaling) pairs for the data interface and consume nearly three times more power than the company’s AD9739A D/A converter.
“The AD9739A converter allows cable head-end equipment manufacturers to simplify and reduce their signal chain footprint while enabling operators to continue providing their customers with improved next-generation services, such as interactive TV, high-definition broadcasts and new specialty channels,” said Chris Jacobs, product line director, High-speed D/A Converter group, Analog Devices.
The D/A converter features a proprietary mix-mode function, which supports the high-fidelity digital synthesis of RF signals at up to 3.6 GHz. The combination of best-in-class, 2.5-GSPS bandwidth and 14-bit dynamic range with a direct-to-RF core allows broadband and next-generation wireless equipment designers to use a single-transmit D/A converter architecture that eliminates a low-pass filter and one mixer or modulator stage.
The converter is well suited for a broad range of applications, including wireless-communications equipment, instrumentation and defense electronics. The device provides multi-carrier capability up to the Nyquist frequency in baseband mode and uses the company’s mix-mode function to generate RF signals in the second and third Nyquist zones.
The AD9739A 14-bit D/A converter operates from 1.8-V and 3.3-V supplies for maximum power consumption of 1.1 W. Low noise and intermodulation distortion performance enable high quality synthesis of wideband signals up to 1 GHz, while a dual-port interface with double-data-rate LVDS data receivers supports the maximum conversion rate of 2.5 GSPS. Output current is programmable from 8.7 mA to 31.7 mA.
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