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-mum BiCMOS process, but it is compatible with most CMOS and BiCMOS fabrication processes. The entire die area is approximately 0.4 mm², including all test pads and dummy devices. Theoretical analysis and experimental results show that the output noise spectral density is 40 nV/radicHz with a bias current of 20 muA. Moreover, the peak-to-peak output noise in the 0.1-10 Hz band is only 4 muV. The untrimmed reference has a mean output voltage of 190.9 mV at room temperature, and it has a temperature coefficient in the -40degC to +125degC range of 11 ppm/degC (mean) with a standard deviation of 5 ppm/degC.