Patent ID: 6304201
Filing Date: 2001-10-16
Classification: H03M

Abstract:
A precision digital-to-analog converter that converts a digital input signal into an analog signal at an output port, comprising:a binary-weighted resistive-ladder primary current source that generates binary-weighted primary currents;primary current switches which each selectively couple a respective one of said binary-weighted primary currents to said output port in response to a respective bit of said digital input signal;a current coupler that mirrors one of said binary-weighted primary currents to thereby generate a binarily-related most-significant-bit trim current;at least one binary-weighted resistive-ladder trim current source that receives said most-significant-bit trim current and, in response, generates binary-weighted trim currents;a current mirror that selectively mirrors and combines said most-significant-bit trim current with said binary-weighted trim currents to thereby selectively reverse their direction; andtrim current switches which each selectively couple a respective one of said binary-weighted trim currents to one of said primary current switches for a linearizing adjustment of that switch's binary-weighted primary current.