Dynamic element matching in D/A converters with restricted scrambling

Inaccurate matching of the analog sources in a D/A converter causes a signal-dependent error in the output. This distortion can be transformed into noise by assigning the digital control to the analog sources randomly, which is a technique referred to as dynamic element matching. In this paper, we present a dynamic element matching technique where the scrambling is restricted such that the glitches in the converter are minimized. By this, both the distortion due to glitches is reduced, and the signal-dependent error due to matching is suppressed. A hardware structure is proposed that implements the approach, and the operation of the hardware is described. Simulation results indicate that the method has a potential of yielding as good reduction of glitches as the optimal thermometer-coded converter and a signal-dependent error level that is almost as low as achieved with prior dynamic element matching techniques.