Patent ID: 6653961
Filing Date: 2003-11-25
Classification: H03M

Abstract:
A multiplying digital-to-analog converter (MDAC) that converts an input signal to an analog output signal with a conversion gain that corresponds to a digital command signal, comprising:a digital-to-analog converter that includes a reference transistor and associated current mirrors whose currents are passed in response to said digital command signal to form said analog output signal wherein said reference transistor has a reference control terminal and a reference current terminal that receives said input signal; a main current source; a drive transistor that has a drive control terminal and a drive current terminal wherein said drive control terminal is coupled to said main current source and said drive current terminal is coupled to said reference control terminal; a pass transistor coupled between said main current source and said reference current terminal; a diode-coupled transistor; and a differential amplifier that has a first input terminal coupled to said diode-coupled transistor and a second input terminal coupled to said reference current terminal and also has an output terminal coupled to drive said pass transistor.