Looking for info about DAC using MOSFET

Hello I want some material to study about DAC can someone provide me material or site links to know basic circuit diagram of DAC using MOSFET.I tried searching net but in vain.i would appreciate it

have u got ckt if yes then plz send me

The simplest DAC is with PWM. You generate (with microcontroller or fpga) a square wave with variable on-time, and constant frequency. This way, the average voltage varies with the duty cycle (on-time divided by period). A simple RC low pass filter will remove the higher frequencies in the signal, and you get your analog voltage.