A two-stage weighted capacitor network for D/A-A/D conversion

A two-stage weighted capacitor network for A/D and D/A conversion utilizing a feedback amplifier is described. The two-stage weighted capacitor DAC requires a smaller range of capacitor values then the conventional weighted capacitor DAC and is not subject to the nonlinear effects of parasitic capacitance. Experimental results of such a DAC implemented using a conventional n-channel metal-gate MOS process are presented. A discussion of the comparative accuracy and area of one- and two-stage weighted capacitor DAC´s on the basis of capacitor tracking is given.