AVX, TAC 0805, capacitors

Tantalum caps eliminate piezo noise in mobile phones

News Release from: AVX
08/08/2006

TAC 0805 2.2µF 25V tantalum capacitors from AVX provide good filtering performance for backlighting control of small LCD displays in mobile phones.

Currently, a 1µF 0805 MLCC capacitor stabilises the output from the LED driver in all mobile phones, and is used for the 1 MHz PWM output to support the LEDs. It is the two secondary frequencies (140 Hz and 1.3 KHz), which occur when the LED goes on/off, that causes piezo noise on the ceramics. At these frequencies, the Multi Layer Chip Ceramics - particularly the higher CV parts - will be worse. However, at 140Hz, all will hum.

TAC 0805 devices have been especially developed for this application to operate at frequencies 1 MHz and below, guaranteeing the user reliable, noise-free operation.

The first models incorporating TAC tantalums are currently in pre-production with a major European cellular phone manufacturer.