This application note examines two different technologies for Class D (switch mode) amplifiers: pulse-width modulation (PWM) and spread-spectrum modulation. Conventionally, PWM Class D amplifiers require costly, bulky filtering components to reduce the electromagnetic interference (EMI) generated by its near rail-to-rail swings and fast-switching frequency. Now, however, spread-spectrum-modulation technology for Class D amplifiers enables designers to eliminate these filtering components without degrading audio performance or amplifier efficiency.