A curvature compensated bandgap reference with low drift and low noise

A low temperature drift and low noise curvature-compensated CMOS bandgap reference is proposed. A dual-differential input pair amplifier was employed to add compensation with a high-order term of T ln T to the traditional 1st-order compensated bandgap. To reduce the offset of amplifier and output noise of bandgap reference, input differential pairs are large-sized PMOS. With a low dropout regulator stage, the voltage reference was increased to 3V. The voltage reference´s temperature curvature is further corrected by 8-bit resistor trimming network. To avoid degrading the precision, noise performance is properly taken into account. The chip was fabricated by using TSMC´s 0.35μm CMOS process. The temperature coefficient was measured only to be 2.1 ppm/°C over -40~125 °C after trimming. The output noise is 42 μVrms from 0.1Hz to 10Hz.