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Filters pass more audio, less noise than discrete or integrated alternatives

Geneva—STMicroelectronics has developed a miniature filter that will help handset designers improve noise reduction in phones with MP3 capability.

The EMIF02-SPK02F2 occupies 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, the EMIF02-SPK02F2 is also applicable in notebook and desktop PCs, car audio systems and personal MP3 players.

According to ST, the filters offer high attenuation and low series resistance, helping to 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, ST said.

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.

Pricing: $0.16 each for orders over 10,000 pieces.
Availability: Full production.
Datasheet: Click here.

STMicroelectronics, www.st.com

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