Design of Low-Power 16-Bit R-2R Digital-to-Analog Converter for Effective Biomedical Signal Processing

Digital-to-analog converter (DAC) is a part of various biomedical signal processing systems. DAC is one of the essential blocks optimizing the performance of various analog-to-digital converters (ADCs) such as SAR-ADC, Delta-Sigma ADC. In this paper, a 16-bit DAC is designed and analyzed that can be used in various applications of ADCs specifically useful in effective biomedical data processing. A design of resistor-2 resistor (R-2R) type DAC based on binary weighted resistors is implemented using 16-bit resolution at sampling rate of 500 MS/s. The main components of the design are R-2R ladder, Switch and operational amplifier. During the design of R-2R DAC op-amp, a current mirror circuit is used that provides a single-ended voltage signal without having any losses. In addition to that, it also uses RC coupling for blocking the DC part of the signal and improves the closed loop stability. All the work was carried out by using cadence virtuoso editor tool. The DAC is designed and simulated at 90 and 45 nm CMOS technology and a comparative analysis is done. The result obtained matches the desired specifications of DAC and it is more efficient and can be used for high-speed applications.