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 brief, a low -voltage bandgap reference using transimpedance amplifier that does not hav e 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-mu m CMOS process (V-TN approxi mate to 0.53 V and V-TP approximate to -0.91 V) with bipolar option. The va riations of the output voltage over temperature (0 degrees C less than or e qual to T less than or equal to 100 degrees C) were measured to be less tha n +/-1%.