Patent ID: 6693570
Filing Date: 2004-02-17
Classification: H03M

Abstract:
Digital-to-analog (DA) conversion circuitry comprising:a DA converter for converting digital data to an analog voltage substantially corresponding to the digital data; a first input port for receiving input data to be converted in a digital form; a second input port for receiving test data in a digital form; a selector operative in response to a mode signal for selectively connecting either one of said first and second input ports to said DA converter, said selector connecting said second input port to said DA converter when the mode signal designates a test mode; a voltage holding circuit interconnected to said DA converter for holding the analog voltage in response to a sampling signal to output the analog voltage held as a hold voltage; and a comparing circuit interconnected to said DA converter and said voltage holding circuit for producing a resultant signal associated with a difference between the analog voltage output from said DA converter and the hold voltage.