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 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-mu m CMOS process (V-TN approximate to 0.53 V and V-TP approximate to -0.91 V) with bipolar option. The variations of the output voltage over temperature (0 degrees C less than or equal to T less than or equal to 100 degrees C) were measured to be less than +/-1%.