A 0.81 ppm/°C, 11.7 μA Voltage Mode Bandgap Reference with V_th-based Piecewise Compensation

This paper describes a threshold voltage based ($\mathrm{V}_{\text {th }}$-based) piecewise compensated voltage-mode bandgap reference (BGR) with low temperature coefficient (TC) and low current consumption for high precision applications. The $V_{\text {th }}$-based piecewise compensation ($\mathrm{V}_{\mathrm{th}}-\mathrm{PC}$) circuit utilizes the principle that the magnitude of threshold voltage $\left(V_{t h}\right)$ varies with the size of the MOS transistor. It generates piecewise compensation current by comparing the thermal voltage $\left(V_{T}\right)$ term and the $V_{\text {th }}$ term instead of comparing currents, effectively reducing current consumption. Designed in 180 nm CMOS technology, the simulated reference voltage ($V_{\text {REF }}$) of the BGR is ${1. 2 1} \mathrm{V}$, with the TC of $0.81 \mathrm{ppm} /^{\circ} \mathrm{C}$ for TT process corner from $-40^{\circ} \mathrm{C}$ to $125^{\circ} \mathrm{C}$. After trimming, the TC of $V_{\text {REF }}$ is $0.98 \mathrm{ppm} /^{\circ} \mathrm{C}$ and $1.51 \mathrm{ppm} /^{\circ} \mathrm{C}$ for FF and SS process corner, respectively. The total current consumption is only $11.7 \mu \mathrm{~A}$ at room temperature with a line regulation (LR) of $0.035 \% / \mathrm{V}$.