A partial tree vector quantizer dynamic element matching technique for audio Δ-Σ converters

Multi-bit Δ-Σ modulators are widely used in performing accurate, low-power, and low cost analogue-to-digital conversion (ADC). One of its major limits is the internal feedback digital-to-analogue converter (DAC) non-linearity. It generates unwanted tones and noise in the band of interest, which makes impossible to achieve the signal quality required in audio products. Authors have overcome this difficulty by designing mismatch-shaping techniques, also called Dynamic Element Matching (DEM). We propose in this paper a new vector-based DEM that we have added to a 4^th order continuous-time ADC. It achieves good audio performances for a reasonable gate count.