TI pushes the limits of low power in three DSPs - Embedded.com

TI pushes the limits of low power in three DSPs

Houston, Tex.– Three new parts in Texas Instruments Inc.'s C5000 DSP lineup are the first standard products to implement the company's full bag of power-management tricks. Targeting power-sensitive applications ranging from wireless communications to portable media, the chips are supported by a tool set that grew out of a partnership with National Instruments Corp. that lets designers model and adjust a chip's power consumption on an application-by-application basis.

While the call from portable-system designers for lower-power DSPs with high performance and low cost has been constant, so too has been the need for more visibility and control over system power usage, said Leon Adams, worldwide manager of DSP product marketing at TI. “We and others have talked a lot about milliwatts/megahertz when it comes to DSPs,” he said, “but there's much more to the power story than that.”

Power can be optimized on two fronts, Adams said: standby power and operating power. “Only 20 percent of a system's time is spent in operating mode, so optimizing standby power is very important.” Furthermore, he said, all functions are in use for only 20 percent of the time a system is in operating mode. TI therefore focused on reducing standby power by using low-leakage processes and incorporating numerous idle and standby states, said Adams. Standby power for the three new DSPs ” the C5503, C5507 and C5509A ” is 0.12 mW at 1.2 volts. Each operates at up to 200 MHz.

The company attacked operating power on various fronts. Each of the three parts is based on a core that consumes 58 mW at 108 MHz. The three have differing amounts of on-chip SRAM ” from 64 to 256 kbytes ” to reduce off-chip accesses and allow for a more efficient code fit. In addition, peripherals can be rapidly turned off when not in use and turned on again when needed. Finally, dynamic voltage and frequency scaling has been incorporated.

The TI5503 Architecture.

Other companies have introduced chips with hooks to control frequency and voltage levels dynamically, said Will Strauss, president of Forward Concepts, citing Intel Corp.'s Xscale and Analog Devices Inc.'s Blackfin as examples. “However, I don't know of any tools available from those two [companies] or others that allow a designer to really manage power consumption under dynamically changing conditions.”

While other companies are content to put every possible unused circuit in idle mode, Strauss said, there can be many intermediate conditions between idle and full power that could preserve battery life if properly managed.

The power-measurement tool developed with National Instruments represents TI's first partnership with an outside company on such a tool. “National Instruments is very good at this, so we saw no reason to go do it ourselves,” Adams said. Priced at $885, the tool works in NI's LabView development environment and is available now. It allows a designer to visually measure and analyze net power and to compare net vs. planned power, TI said.

A DSP evaluation module from Spectrum Digital Inc. will be available in beta version in the third quarter for $1,495. The module can evaluate all three DSPs. It can also be used with NI's tool to measure power for specific application code.

Prices for the C5503 DSP, with six-channel direct-memory access and a host of ports and timers, start at $7.50 each in quantities of 10,000. The C5507 adds USB 2.0 and a 500-microsecond, 10-bit D/A converter; it starts at $10.50 in similar quantities. The C5509A adds two Multi-MediaCard/Secure Digital ports and sells for $16 each in 10,000s. All parts are sampling now, with production set for August.

For a description of TI's new power design tools, new DSPs and a roadmap of C5000 devices, visit www.ti.com/powerefficientperformance

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