ST Microelectronics has introduced a new device, EMIF06-AUD01F2, which ensures optimum audio performance in cellphones.
The EMIF06-AUD01F2 implements the complete EMI (electromagnetic interference) filtering and ESD (electrostatic discharge) protection for stereo headset output and external and internal microphones within a flip-chip package measuring 2.42 x 1.92mm.
The EMIF06-AUD01F2 eliminates audible handset demodulation noise, or bumble-bee noise, by achieving –25dB attenuation throughout the stop-band 800-2480MHz using high-density 1.3nF PZT (lead, zirconate titanate) capacitors on the microphone lines.
The EMIF06-AUD01F2 also achieves high ESD protection through the combination of integrated TVS (transient voltage suppressor) diodes, low-inductance packaging, and the Z-R-Z pi-filter topology.
The EMIF06-AUD01F2 saves more than 50% of board space compared to previous integrated solutions using two ICs with external resistors, and up to 77% compared to alternative discrete solutions.
All necessary biasing circuitry is also integrated, as well as a 10 ohm series resistor in the speaker output, thereby minimising external components. The low package profile of 0.65mm also helps designers implement high functionality within slim handset styles.
The space-saving advantages are combined with better audio performance and higher ESD protection compared to integrated or discrete alternatives. The integrated TVS diodes have a 20V peak clamping voltage, enabling the device to meet IEC61000-4-2 level 4 ESD protection at the external pins.
Total harmonic distortion (THD) is less than –75dB, while the EMIF06-AUD01F2 achieves high audio-power transfer by delivering 135mA per speaker channel ensuring good sound reproduction. This is achieved due to the high thermal efficiency of the wafer-level flip-chip package, which supports 285mW total continuous power dissipation.