Introduction

A wide variety of microcontroller applications require the use of analog output signals. Many low-cost microcontrollers have peripherals to process analog input signals, such as an Analog-to-Digital Converter (ADC), but often do not have a Digital-to-Analog Converter (DAC) included. Of course, there are options for external DACs; however, those may require extra I/O connections or PCB space, and will add cost to the application. Fortunately, most microcontrollers offer a Pulse-Width Modulation (PWM) module, which can be combined with a low-pass filter to create an analog output. This technical brief highlights the use of a low-pass filter to transform a PWM signal into an analog signal.