Low-Noise, High PSRR and Temperature-Stable Voltage Reference for MEMS-Based Acceleration Sensor Systems

This paper presents a voltage reference for MEMS-based accelerometer systems in consumer-based applications, where stability under varying temperature conditions is essential for accurate sensor output. Furthermore, a high-power supply rejection ratio (PSRR) is critical for maintaining sensor performance and ensuring reliable, precise measurements. Therefore, dual PSRR enhancement stages are employed to achieve high PSRR. The first stage utilizes a flipped voltage follower to suppress the power supply noise, while the second stage isolates the reference voltage from variations in the power supply. To minimize output noise, a MOSFET low-pass filter with a feedback technique is integrated into the second stage of the PSRR, stabilizing the PSRR while reducing the output noise. A temperature-stable reference voltage is generated through a load NMOS transistor operating in the saturation region, with its gate connected to another NMOS transistor functioning as a resistor. The proposed temperature-stable voltage reference has been designed and simulated using 180[Formula: see text]nm CMOS technology. The simulation results indicate that the circuit achieves a temperature coefficient of 7[Formula: see text]ppm/ ∘ C across a temperature range of [Formula: see text]40 ∘ C to [Formula: see text]C. It provides a stable reference voltage of 0.4467[Formula: see text]V while operating within a supply voltage range of 1[Formula: see text]V to 3[Formula: see text]V. The line sensitivity is measured at 0.089%/V, and the PSRR is [Formula: see text]118.97[Formula: see text]dB at 100[Formula: see text]Hz and [Formula: see text]118.9[Formula: see text]dB at 10[Formula: see text]kHz. The circuit exhibits a low power consumption of 0.57[Formula: see text] [Formula: see text]W and occupies a compact area of 0.001[Formula: see text]mm 2 . The noise analysis focuses on the frequency range of 10[Formula: see text]Hz to 10[Formula: see text]MHz, which corresponds to the operational bandwidth of the targeted consumer-based sensor application. It exhibits output noise levels of [Formula: see text]Hz at 10[Formula: see text]Hz and 14.8[Formula: see text]nV/[Formula: see text]Hz at 100[Formula: see text]Hz.