Early Bluetooth hype certainly overshadowed the early days of actual products, but today the technology is finding use in most every mobile handset and even in stereo music applications. Diverse applications are leading to ICs with more integrated features and more flexibility.

CSR took exactly that approach with the BlueCore5-FM IC. The chip offers flexibility in terms of battery life relative to range. With no external power amplifier, the IC offers Class 1, 100m range and provides output power of 10 dBm. This feature enables streaming FM radio from a handset to remote headphones over Bluetooth, giving the same flexibility as today's popular wireless headphones. Alternatively, the chip can support Bluetooth Class 2, 10m range with extended battery life.

The IC includes the FM tuner function along with Bluetooth support. The addition of FM radio to handsets has become an attractive feature in low-end models and is set to grow in the next few years. But designing a new radio into a handset is difficult, adding components, real estate, cost, power consumption, and-unfortunately-RF interference. CSR's BlueCore5-FM combines a sensitive FM radio receiver (an impressive -111 dBm) and Bluetooth functions on a single chip and offers some unique advantages.

Co-locating radios in ultracompact systems can lead to severe interference and audio-quality problems. BlueCore5-FM's innovative design combats interference with a patented technique, blocking tones as much as 30 dB stronger than the wanted FM signal, whether off-chip or on-chip. BlueCore5-FM is highly integrated and requires just 15 external components for complete Bluetooth and FM tuner functions-only three are for the FM radio. A separate FM radio IC typically requires an additional 3×3-mm footprint and 10 or more external components.