The TPA2038D1 is a 3.2 W into 4-ohm (10% THD) high efficiency filter-free class-D audio power amplifier. The GAIN pin sets gain to either 6 dB or 12 dB. Features like 95% efficiency, 1.5 mA quiescent current, 0.5 µA shutdown current, 81 dB PSRR, 20 µV output noise, and improved RF immunity make the TPA2038D1 class-D amplifier ideal for cellular handsets. A start-up time is within 4 ms with no turn-on pop. The TPA2038D1 is available in a 1.21 mm x 1.16 mm, 0.4 mm pitch wafer chip scale package (WCSP).