A Sub-1-V low-noise bandgap voltage reference

A new sub-1-V bandgap voltage reference is presented in this paper, which has advantages over the prior arts in terms of output noise and compatibility with several fabrication processes. The topology allows the reference to operate with a supply voltage as low as 1 V by employing the reverse bandgap voltage principle (RBVP). It also has an attractive low-noise output without the use of a large external filtering capacitor. The design was fabricated with a 0.5-mu m BiCMOS process, but it is compatible with most CMOS and BiCMOS fabrication processes. The entire die area is approximately 0.4 mm(2), including all test pads and dummy de-: vices. Theoretical analysis and experimental results show that the output noise spectral density is 40 nV/root Hz with a bias current of 20 mu A. Moreover, the peak-to-peak output noise in the 0.1-10 Hz band is only 4 mu V. The untrimmed reference has a mean output voltage of 190.9 mV at room temperature, and it has a temperature coefficient in the -40 degrees C to +125 degrees C range of 11 ppm/degrees C (mean) with a standard deviation of 5 ppm/degrees C.