WAYNE, N.J. -- RF Micro Devices Inc. has started sampling a CMOS Bluetooth system-on-chip (SoC) device that supports data rates up to 3 Mbits/second.
Bluetooth wireless communication is on the cusp of a data rate ramp-up in the wake of the Bluetooth Special Interest Group's adoption of Enhanced Data Rate (EDR) specifications in June. The EDR specs replace the Gaussian frequency-shift keying modulation scheme used in existing 1-Mbit Bluetooth devices with two new modulation approaches: differential quadrature phase-shift keying, which pushes data rates to 2 Mbits/s; and an eight-level DPSK that pushes data rates to 3 Mbits/s.
In terms of throughput, this change will take Bluetooth from the 700-kbit/s rate of current Bluetooth 1.2 systems and move them into the 2.1-Mbit/s range, said Joel Linsky, staff systems engineer at RF Micro Devices (Greensboro, N.C.).
Power savings
Other chip makers offer or are preparing Bluetooth chips featuring the faster EDR transfers.
OEMs are pleased about the EDR bandwidth boost because it will allow them to improve the throughput and quality-of-service of their Bluetooth links, Linsky said. By supporting faster data transfers, EDR will allow OEMs and chip manufacturers to increase the power savings in their Bluetooth design, he added.
Compliant with the Bluetooth 1.2 and EDR specs, RF Micro's SiW4000 chip integrates an ARM7TDMI processor to handle baseband-processing tasks, plus a direct-conversion radio front end that includes 50-ohm matching at the antenna port. The SoC also includes a fractional-N synthesizer, an on-chip low-dropout regulator that allows the IC to hook directly to a battery and an optional regulator that allows developers to use the chip in a switching mode.
Cambridge Silicon Radio announced sample availability of a Bluetooth core with EDR features earlier this summer, and said it would be in full production in September. It also announced a ROM-only version of the chip, which is to sample in the third quarter and enter production in the fourth.
The new modulation schemes needed for EDR required silicon-level changes in RF Micro's designs. The company had to make hardwired changes in the baseband portion of its existing Bluetooth design in order to support the phase-shift keying modulation schemes. Additionally, RF Micro says it increased the speed of the chip's UART interface and added a synchronous serial interface to support higher-throughput transfers to chips connecting to the Bluetooth IC.
RF Micro will offer the Bluetooth device in three versions: a 45 x 45-mm box (1 mm high) in a ROM-only version; a stacked flash configuration (1.4 mm high); and a 96-ball BGA that features external interfaces for linking up with off-chip flash memory.
To implement any of the chips on a board, designers will need six capacitors, one inductor and one bandpass filter, the company said.
The SiW4000 Bluetooth IC is sampling to select customers now. General sampling is slated for the first quarter of 2005, while mass production is planned for the third quarter.
