A sub-1 V, 26 μw, low-output-impedance CMOS bandgap reference with a low dropout or source follower mode

Abstract

We present a low-power bandgap reference (BGR), functional from sub-1 V to 5 V supply voltage with either a low dropout (LDO) regulator or source follower (SF) output stage, denoted as the LDO or SF mode, in a 0.5-μm standard digital CMOS process with V tn≈ 0.6 V and |V tp| ≈ 0.7 V at 27 °C. Both modes operate at sub-1 V under zero load with a power consumption of around 26 μW. At 1 V (1.1 V) supply, the LDO (SF) mode provides an output current up to 1.1 mA (0.35 mA), a load regulation of ±8.5 mV/mA (±33 mV/mA) with approximately 10 μ s transient, a line regulation of ±4.2 mV/V (±50μV/V), and a temperature compensated reference voltage of 0.228 V (0.235 V) with a temperature coefficient around 34 ppm/° C from -20°C to 120 °C. At 1.5 V supply, the LDO (SF) mode can further drive up to 9.6 mA (3.2 mA) before the reference voltage falls to 90% of its nominal value. Such low-supply-voltage and high-current-driving BGR in standard digital CMOS processes is highly useful in portable and switching applications. © 2010 IEEE.published_or_final_versio