A 12-bit Multi-Channel R-R DAC Using a Shared Resistor String Scheme for Area-Efficient Display Source Driver

Abstract

This paper presents a 12-bit multi-channel resistor-resistor-string digital-to-analog converter (RRDAC) using a shared R-string scheme for an area efficient display source driver. The proposed scheme relaxes the required equivalent resistance value of R-string of each channel by sharing a channel R-string that is simultaneously connected to the same tap of a global R-string. Thus, the overall DAC size can further be minimized while maintaining the same accuracy. That is, if the proposed scheme is implemented with the same size as the conventional RRDAC, higher accuracy can also be achieved. For the verification of shared resistor string scheme, a 12-bit RRDAC was fabricated using 0.35-mu m standard CMOS technology. Compared with the conventional RRDAC, the proposed design showed a 15% reduction in size, a DNL of 0.49 LSB and an output voltage deviation of 9.3mV for eight different chips. Also, the area per channel was 0.0465 mm(2).