A Precision CMOS Voltage Reference Exploiting Silicon Bandgap Narrowing Effect

A compact voltage-mode bandgap voltage reference (BGR) is presented. Instead of using overhead circuits, the silicon bandgap narrowing effect is exploited for bipolar junction transistor's (BJT) curvature reduction and residual curvature correction. Prototype measurements in a 0.18-μm standard CMOS process show that the curvature of the BJT is effectively reduced from its inherent 3.6 mV to 1.4 mV. The proposed BGR measures a minimum temperature coefficient of 8.7 ppm/°C from -55°C to 125°C by batch trimming one resistor. After a curvature trimming, it further improves to 4.1 ppm/°C. The BGR has a minimum supply voltage of 1.3 V, 4.3 μA nominal current consumption, 0.03%/V line sensitivity, and 2 mV/mA load sensitivity at 25°. The output rms noise in the 0.1~10 -Hz band measures 10.23 μV.