A 2.79 μV_rms Noise, 3.6 ppm/°C TC Bandgap Reference for Portable Biopotential Signal Monitoring Systems

A low-offset, low-noise, high-precision bandgap reference (BGR) for portable biopotential signal monitoring systems is proposed in this paper. Using feedback enhancement technology, the offset voltage and noise of the op-amp are reduced by approximately 23 times when equivalent to the reference output compared to the traditional structure. To reduce the deviation of the reference output under various corners and device mismatch, high-precision base current compensation technology is also adopted. The proposed BGR is implemented using the $0.18 \mu \mathrm{~m}$ CMOS technology, with a chip area of $0.142 \times 0.258 \mathrm{~mm}^{2}$. The test results indicate that the BGR outputs a 0.6 V reference voltage at a power supply of 1.2V, with a current consumption of $31 \mu \mathrm{~A}$. The integrated noise of $0.1 \sim 10 \mathrm{~Hz}$ is $2.79 \mu V_{\text {rms }}$. The output voltage’s temperature coefficient (TC) is $3.6 \mathrm{ppm} /^{\circ} \mathrm{C}$ in the range of $-40 \sim 125^{\circ} \mathrm{C}$.