A low power CMOS bandgap voltage reference with enhanced power supply rejection

A low power low temperature-coefficient bandgap voltage reference features high power supply rejection (PSR) for low dropout regulators (LDOs) is presented in this paper. An optimized PSR enhance stage is inserted in opamp based CMOS bandgap voltage reference, which introduces supply spurious into the bandgap loop so as to maintain a constant gate-source voltage in the upper current mirror; this improves the PSR performance about 38 dB. A prototype of the bandgap voltage reference is implemented in TSMC 0.6 ¿m double poly, double metal, CMOS technology, occupying 0.07 mm² active silicon areas. The measured PSR are -82.8 dB @ 50 kHz and -70 dB @ 100 kHz, respectively; and, the supply current is 9 ¿A, the temperature-coefficient is 15ppm/°C at 2~5 V supply voltage, the line regulation is 54 ¿V/V.