A curvature calibrated bandgap reference with base—emitter current compensating in a 0.13 μm CMOS process

In bandgap references, the effect caused by the input offset of the operational amplifier can be effectively reduced by the utilization of cascade bipolar junction transistors (BJTs). But in modern CMOS logic processes, due to the small value of β, the base—emitter path of BJTs has a significant streaming effect on the collector current, which leads to a large temperature drift for the reference voltage. To solve this problem, a base—emitter current compensating technique is proposed in a cascade BJT bandgap reference structure to calibrate the curvature of the output voltage to temperature. Experimental results based on the 0.13 μm logic CMOS process show that the reference voltage is 1.238 V and the temperature coefficient is 6.2 ppm/°C within the range of −40 to 125 °C.