Combined Audio Filtering and ESD Protection Save Board Space
STMicroelectronics introduces its EMIF06-AUD01F2 for optimal audio performance in feature-rich cellphones. The device 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 × 1.92 mm. It eliminates audible handset demodulation noise, or ‘bumble-bee’ noise, by achieving –25 dB attenuation (S21) throughout the stop-band from 800 to 2,480 MHz, using high-density 1.30 nF PZT (lead, zirconate titanate) capacitors on the microphone lines. The device 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.