800-nA Process-and-Voltage-Invariant 106-dB PSRR PTAT Current Reference

摘要

This brief presents a novel process-and-voltage-invariant proportional to absolute temperature (PTAT) current reference. The proposed circuit is designed and fabricated in 180-nm mixed-mode CMOS technology. Measurement results show that the $I_{rm PTAT}$ varies only by $pm$2.4% $(pm 3sigma/mean)$ across 18 test chips. One thousand Monte Carlo simulation runs show that the maximum deviation $(pm3sigma/mean)$ from the desired value of the PTAT current is $pm$5.4%. The proposed PTAT current reference uses a process, voltage, and temperature (PVT)-invariant resistor circuit having $R_{rm ON}$ variation reduced by 4.2 times, as compared to a fixed biased MOSFET. The proposed PTAT current reference draws only 800-nA current from the supply voltage and also exhibits a high dc power supply rejection ratio (PSRR) of 106 dB. This brief also presents a PVT-invariant transconductance using the implemented PVT-invariant resistor.