Design and Simulation of MEMS-Based Digital-to-Analog Converters for In-Plane Actuation

Abstract

A microelectromechanical system-based digital-to-analog converter (MEMS DAC) using a bent beam electrothermal compliant actuator as a single mechanical bit is proposed in this work. Two types of MEMS DAC namely asymmetric and symmetric structures with multi-bent beam actuators in a chevron arrangement are designed, modeled and simulated in MEMS CAD tool CoventorWare. The proposed DACs generate the mechanical displacement at the output from the digital input based on the principle of weighted stiffness which is analogous to an electronic weighted resistor DAC. The DACs are built using a standard SOIMUMPs process, and its coupled electrothermomechanical analysis is carried out to illustrate their performance. The device operates on 5 V which is well suited with conventional CMOS logic and in turn reduces the power consumption of the device. The simulation result shows that symmetric and asymmetric MEMS DACs produce a nonlinear error of 0.5 and 3.5% from its ideal straight line. The nonlinearity error is found to be less in symmetric design due to equal width of bent beam.