Handset audio filter is first to battle ESD

摘要

The EMIF06-AUD01F2 handset audio filter integrates capacitors and TVS diodes in a 2.42 × 1.92-mm flip-chip package, and claims to be the first circuit-protection device to offer complete EMI filtering and ESD protection for handset speaker and microphone channels in portable audio applications. Reducing board-space requirements by more than 50% compared to previous integrated solutions using two ICs with external resistors and up to 77% compared to discrete solutions, the device also combines all necessary biasing circuitry as well as a 10-Ω series resistor in the speaker output. The high-density 1.3-nF PZT capacitors on the microphone lines eliminate audible handset demodulation noise by achieving -25-dB attenuation over the 800 to 2,480-MHz bandwidth, while the integrated TVS diodes, low-inductance packaging, and a Z-R-Z pi-filter topology protect against ESD.