PWM to Voltage Converter – PWM to Voltage Output DAC

Module is a dual 12-bit PWM-to-voltage output DAC with high accuracy. The board is based on the LTC2644 chip. The LTC2644 measures the period and pulse width of the PWM input signals and updates the voltage output DACs after each corresponding PWM input rising edge. The DAC outputs update and settle to 12-bit accuracy within 8μs typically and are capable of sourcing and sinking up to 5mA (3V) or 10mA (5V), eliminating voltage ripple and replacing slow analog filters and buffer amplifiers. The circuit has a full-scale output of 2.5V using the 10ppm/°C internal reference. It can operate with an external reference, which sets the full-scale output equal to the external reference voltage. Each DAC enters a pin-selectable idle state when the PWM input is held unchanged for more than 60ms. The project operates from a single 2.7V to 5.5V supply and supports PWM input voltages from 1.71V to 5.5V. The PWM frequency can be any frequency between 30Hz and 6. 25kHz. The input level can be between 1.71V and 5.5V, set by a separate IO_VCC pin. This project solves many problems associated with filtering a PWM signal to produce an analog voltage, producing a fast-settling, accurate analog voltage in response to a digital PWM input.