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The power of 1VTI demonstrates 1-V DSP for digital wireless phonesIn a breakthrough for ultra-low-power DSP technology, researchers at TI have successfully demonstrated a programmable DSP that operates at 1-V and below. The tested device is the industry's first 1-V, high-performance DSP that performs all the functions of a standard commercial device. Operating at 60 MHz, the 1-V DSP consumes one-fifteenth the power required to operate a comparable 3.3-V DSP, while delivering equivalent performance. To achieve even greater power savings at low frequencies, the test chip can operate down to 0.6-V, and at speeds up to 100 MHz at 1.35-V for higher performance. 3,000 miles on a pint of gas If automakers could reduce automotive fuel consumption like TI has reduced DSP power consumption, it would now be possible to cross the United States via automobile using less than a pint of fuel.
For digital wireless telephones, a targeted application for ultra-low power DSP development, this power savings can translate directly into longer battery life, enabling longer talk time and smaller, lighter-weight mobile phone handsets. With similar improvements in other mobile phone components, it would be possible to talk seven hours a day for more than a week without recharging a battery. "TI's 1-V DSP technology points the way to the future of ultra-low-power computing in a wide range of applications, especially in mobile telephony," said Mike McMahan, director of research and development for the wireless business unit. "Digital wireless phones and other mobile applications will feel the impact first, but eventually other very powerful systems capable of multimedia and other communication tasks will be running on ultra-low-power DSPs similar to this one." To create the test device, TI researchers rescaled an existing 0.6-micron CMOS DSP, the TMS320LC545, using a 0.35-micron CMOS process with 0.25-micron transistor gates. The rescaled test chip contains 1.6 million transistors and is functionally identical to the fully programmable, 16-bit fixed-point 'LC545. At 1-V and 60 MHz, the test chip consumes only 17 milliwatts (mW). By comparison, the 3.3-V 'LC545, which is itself designed for low-power wireless applications, requires approximately 15 times this much power at 60 MHz. Power savings and increased performance result from design innovations as well as process enhancements. Researchers used dual threshold voltages to enhance performance in speed-sensitive portions of the design while still controlling leakage current. For example, memory cells were designed using a standard 300 millivolt (mV) threshold to minimize leakage, while more time critical logic functions in the CPU were built using faster transistors with a lower threshold of 100 mV. Another significant design change was the replacement of the analog phase-locked loop (PLL) of the 'LC545 with a digital PLL that operates at ultra-low voltages and is more reliable than the standard analog version. Integrated RAM and ROMLike its parent 'LC545 DSP, the 1-V DSP features an architecture specifically crafted for digital wireless telephone applications. Features include integrated RAM and ROM to minimize off-chip memory accesses, as well as a rich set of peripheral devices. Multiple on-chip buses support greater parallelism, and specially designed logic structures minimize the number of operations needed to perform algorithms that are commonly used for wireless communication. Software-controlled power-down modes, local clock gating and a carefully designed clock distribution system all serve to minimize power consumption. In addition to pioneering work in low-power DSP design, technologists at TI's DSP Research and Development Center perform research and development in DSP algorithms, architecture and circuit design. The center covers compression, communications, DSP systems and advanced CMOS circuits. Circuit technology investigations include low power and high performance logic as well as mixed signal, data conversion and RF CMOS. The CMOS process used by the 1-V DSP is a precursor of TI's 0.18- micron, 125-million-transistor TImeline technology.
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