More than 75% of cellular handsets will ship with MP3 capability in 2010, making audio performance a focus area for designers. New handset designs will demand improvements in noise reduction that can be enabled by the new EMIF02-SPK02F2 filter, today announced by STMicroelectronics.
The EMIF02-SPK02F2 occupies only 0.89 x 1.26mm of valuable handset pc-board space, and provides filtering for the handset's built-in speaker or a stereo headset output. A single EMIF02-SPK02F2 can also be connected to the microphone input to isolate the handset from external sources of noise, such as other cellphones.
As a member of ST's audio IPAD family, which delivers miniaturized filters for various handheld and mobile-audio applications, the EMIF02-SPK02F2 also delivers performance benefits in notebook and desktop PCs, car audio systems and personal MP3 players.
With high attenuation and low series resistance, the new filters achieve greater noise reduction while preserving audio signal strength better than any other approach. Filters built using discrete components, for example, are difficult to design for tri-band handsets and typically occupy around 72% more board space than the EMIF02-SPK02F2. Alternatively, single-chip passive filters can be as much as 11% larger, and also permit several times more noise at the frequencies used in standards such as GSM. These include signals at 900MHz and 1800MHz, which can be picked up by the handset's audio circuitry, creating audible interference, the so-called 'TDMA' noise.
The EMIF02-SPK02F2 also provides better ESD protection than any existing solution. This performance is necessary, because the level of ESD protection built into chips such as audio ICs is being reduced as ESD-safe manufacturing environments have improved. The implication for product designers is that devices used specifically to meet product-level ESD standards such as IEC EN 61000-4-2 must provide greater protection. To achieve this, the EMIF02-SPK02F2 has a double-clamping structure able to clamp an ESD spike to just 12V compared to the 300V permitted by some ESD protection devices.
The EMIF02-SPK02F2 is in full production, and is available at $0.16 each for orders over 10,000 pieces.