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.