Design of low-voltage bandgap reference using transimpedance amplifier

The minimum supply voltage for implementing a typical bandgap reference is usually over 1.8 V. This minimum is mainly due to the limited input common-mode range of the opamp used in the bandgap reference. In this work, a low-voltage bandgap reference using a transimpedance amplifier that does not have this limitation is proposed and some of the design considerations for the proposed technique are briefly discussed. Based on this technique, a 1.2-V bandgap reference was implemented in a 1.2-/spl mu/m CMOS process (V/sub TN//spl ap/0.53 V and V/sub TP//spl ap/-0.91 V) with bipolar option. The variations of the output voltage over temperature (0/spl deg/C/spl les/T/spl les/100/spl deg/C) were measured to be less than /spl plusmn/1%.