Texas Instruments Inc. and AT&T Microelectronics have launched a semiconductor marketing race, each introducing single-chip digital signal processors they say complete more instructions per second using less power.
Texas Instruments
Dallas-based TI offers two DSP solutions; the 541 DSP for digital cellular telephones and personal digital assistants is available today and the 542 DSP for wireless base stations will be available by the fourth quarter. TI says the processors are 10 times more powerful at handling math-intensive tasks than other computer central processing units.
“Digital is lucrative for a semiconductor company because the semiconductor content is higher,” said Thomas Brooks, product marketing manager for the TI Wireless Communications Business Unit, Semiconductor Group.
The TI processors operate at 50 million instructions per second, or MIPS, and have design enhancements that reduce the number of MIPS consumed to execute the functions required in digital processing, such as voice and channel coding, the company said.
“Our MIPS are more powerful and our architecture is stronger, so it takes fewer MIPS. Our DSPs can do the task quickly then go into idle,” Brooks said.
One chip conducts the analog/digital conversion, digital signal processing and digital/analog conversion. The processor’s core architecture is optimized for wireless technologies, with performance running at 2.7 or 5 volts of power.
The 541 DSP for phones contains 28 kilowords of Read Only Memory and 5 KW of Random Access Memory on chip. The 542 DSP for base stations contains 10 KW of RAM and 2 KW of boot ROM on chip.
TI’s DSPs now handle full-rate Global System for Mobile communications technology, performing voice coding/decoding, demodulation, encryption, channel coding/decoding, interrupt handling and other tasks.
The TI DSPs also can do Interim Standard 54-B (Time Division Multiple Access) technology. TI and Berkeley, Calif.-based TCSI Corp. are jointly developing and licensing a chipset for the IS-136 TDMA standard. TI is working on technology for specialized mobile radio applications, as well as personal communications services technology.
“A lot of the same PCS technology can be reused, with a different flavor,” Brooks said. About 60 percent of TI’s $10.3 billion in revenues now comes from semiconductors; TI expects that by 2000, wireless will bring in half of its revenues.
AT&T
AT&T Microelectronics has introduced the DSP1627, which the company said can process 50 million instructions per second (MIPS) from a 2.7 volt power supply, and 70 million MIPS when running at 5 volts.
It will be available in this year’s third quarter, replacing earlier-generation DSPs that required two chips to share the processing for the modem and voice coding functions.
In terms of power consumption, the new DSP has a drain of only 0.7 milliamps/MIPS at 2.7 volts, AT&T said. That is a 30 percent improvement over the previous-generation AT&T 161X DSP family, the company said.
“The horsepower of this single chip has reduced the DSP count by half,” said Raj Agrawala, AT&T wireless processors product manager.
A combination of high MIPS at low voltage and low-power consumption translates into smaller, lighter-weight phones with increased service between battery recharges, AT&T said.
“It also establishes a new low-power consumption benchmark that will prolong talk time and standby time for the user,” Agrawala said.
The AT&T processor has 36 kilowords of ROM memory and 6 KW of dual-ported RAM available on chip, meeting the requirements for IS-136 TDMA, Japanese digital and GSM technologies.
With chip size reduced, the DSP1627 meets the space requirements for minicell equipment, AT&T said. Additional improvements include an on-chip clock synthesizer to reduce noise levels and the effects of electromagnetic interference and an 8-bit parallel host interface to standard microcontroller protocols, adding a new level of flexibility. A power control manager can deactivate on-chip peripherals, placing them in sleep mode to preserve battery life.
