An 8Ω, 1.75W, 95% efficiency, 0.004% THD+N Class-D amplifier with a feed-forward ADC and feedback filters

An integrated ultralow EMI Class-D amplifier with a feed-forward ADC and feedback filters is demonstrated in a 180 nm CMOS and wire-bonded package. Circuit and architecture techniques, which enables 1.75W into an 8 Ohm speaker, 105 dB dynamic range, 95% efficiency, 0.004% THD+N, and 15.4 dB margin beyond the EN55022 Class B standard, are discussed.