A 0.002-mm2 8-bit 1-MS/s low-power time-based DAC (T-DAC)

Abstract

Digital-to-analogue converters (DACs) are essential blocks for interfacing the digital environment with the real world. A novel architecture, using a digital-to-time converter (DTC) and a time-to-voltage converter (TVC), is employed to form a low-power time-based DAC (T-DAC) that fits low-power low-speed applications. This novel conversion mixes the digital input code into a digital pulse width modulated (D-PWM) signal through the DTC circuit, then converts this D-PWM signal into an analogue voltage through the TVC circuit. This new T-DAC is not only an energy-efficient design but also an area-efficient implementation. Power optimization is achieved by controlling the supply voltage of the TVC circuit with a discontinuous waveform using a low bias current. Moreover, the implementation area is optimized by proposing a new DAC architecture with a coarse-fine DTC circuit. Post-layout simulations of the proposed T-DAC is conducted using industrial hardware-calibrated 0.13 μm. Complementary metal oxide semiconductor technology with a 1 V supply voltage, 1 MS/s conversion rate, and 0.9 μW power dissipation.