Abstract: A CMOS bandgap reference (BGR) without a resistor,with a high power supply rejection ratio and output below 1V is proposed.The circuit is suited for on-chip voltage down converters.The BGR is designed and fabricated using an HJTC 0.18μm CMOS process.The silicon area is only 0.031mm2 excluding pads and electrostatic-discharge (ESD) protection circuits.Experimental results show that the PSRR of the proposed BGR at 100Hz and 1kHz achieves,respectively,-70 and -62dB using the pre-regulator.The proposed BGR circuit generates an output voltage of 0.5582V with a variation of 1.5mV in a temperature range from 0 to 85℃.The deviation of the output voltage is within 2mV when the power supply voltage VDD changes from 2.4 to 4V.

Key words: CMOS bandgap reference, current source circuit, PSRR, pre-regulator