TI Converts Data for Wireless Communications

By
iApplianceWeb
(08/27/01, 09:27:33 AM EDT)

Texas Instruments, Inc., has unveiled a new family of 125-MSPS dual digital-to-analog converters (DAC) providing 10, 12, and 14-bit resolution in pin-compatible packages. The DAC290x family makes sense for communications systems utilizing quadrature modulation, such as cellular and paging base stations, point-to-point microwave systems, wireless local loop (WLL), wireless LANs, and cable modems. Additionally, the wide supply range (single +3.3V and/or +5V) and low power (310mW power dissipation) make the DAC290x family suitable for test instrumentation and battery-powered applications.

The DAC290x family consists of the DAC2904 (dual 14-bit), DAC2902 (dual 12-bit), and DAC2900 (dual 10-bit). All devices in the family are pin-compatible, allowing a resolution upgrade path with the same board design. Furthermore, the standard pin-configuration followed by the DAC290x family gives customers a higher dynamic performance, lower power, and lower price alternative to pin-compatible competitive devices, and simplifies the in-system evaluation and qualification process.

Designed for use in the transmit section of communications systems, the dual channels offered by the DAC290x are ideal for quadrature modulated signal conversion by providing simultaneous processing and excellent I/Q channel matching. This is critical for maintaining low error-vector magnitudes in systems deploying QAM (quadrature amplitude modulation) or other advanced multilevel modulation schemes.

"Transmit architectures utilizing some form of analog quadrature modulation represent a proven system solution. With the DAC290x family, designers can upgrade their systems for wider bandwidth and higher data rate applications, such as EDGE, while avoiding the high cost of complete redesigns," said Stephan Baier, strategic marketing engineer of TI's high-speed data converter products. "The unmatched price/performance ratio of our new DAC290x family offers the perfect solution for any designer going through a cost reduction cycle without having to sacrifice performance. For example, the narrowband spurious-free dynamic range on the DAC2904 is well above the 80dB mark, while wideband ACPR performance is at an impressive -69dB level."

The DAC2904 and DAC2902 offer 81dB spurious-free dynamic range (SFDR) at 5MHz output frequency and 52MSPS update rate. The DAC2900 offers 80dB SFDR at 5MHz output frequency and 52MSPS update rate. The differential current outputs support a high compliance range of up to +1.25V while maintaining excellent distortion performance.

Each device features a power-down mode (23mW), allowing for significant power reduction while in standby. Other features of the DAC290x family include differential current outputs, an adjustable 2-20mA full-scale output range, and an internal +1.25V reference.

All three devices in the DAC290x family are available now and are packaged in a TQFP-48. Suggested resale pricing for 1,000 piece quantities is: DAC2904 ($19.95), DAC2902 ($15.25), and DAC2900 ($9.10).

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Texas Instruments