This　study　presents　a　high-fidelity　and　high-efficiency　digital　class-D　audio　power　amplifier　(CDA),　which　consists　of　digital　and　analog　modules.　To　realize　a　compatible　digital　input,　a　fully　digital　audio　digital-to-analog　converter　(DAC)　is　implemented　on　MATLAB　and　Xilinx　System　Generator,　which　consists　of　a　16x　interpolation　filter,　a　fourth-order　four-bit　quantized　delta-sigma　(ΔΣ)　modulator,　and　a　uniform-sampling　pulse　width　modulator.　The　CDA　utilizes　the　closed-loop　negative　feedback　and　loop-filtering　technologies　to　minimize　distortion.　The　audio　DAC,　which　is　based　on　a　field-programmable　gate　array,　consumes　0.128　W　and　uses　7100　LUTs,　which　achieves　11.2%　of　the　resource　utilization　rate.　The　analog　module　is　fabricated　in　a　0.18　μm　BCD　technology.　The　postlayout　simulation　results　show　that　the　CDA　delivers　an　output　power　of　1　W　with　93.3%　efficiency　to　a　4　Ω　speaker　and　achieves　0.0138%　of　the　total　harmonic　distortion　(THD)　with　a　transient　noise　for　a　1　kHz　input　sinusoidal　test　tone　and　3.6　V　supply.　The　output　power　reaches　up　to　2.73　W　for　1%　THD　(with　transient　noise).　The　proposed　amplifier　occupies　an　active　area　of　1　mm2.　©　2021　Cong　Wei　et　al.