a multiplying digital to analog converter comprising a digital to analog converter having a plurality of capacitors coupled in parallel , applying first signals to the capacitors during a sampling period , and applying second signals to the capacitors during an amplifying period , and an amplifier including a first amplifier electrically coupled to the digital to analog converter ; a second amplifier electrically coupled to the first amplifier ; and a first switch electrically coupled between an input end and an output end of the second amplifier , being turned off during a sampling period , and being turned off during an amplifying period .