A 73-dB PSR Trimless CMOS-Only Subthreshold Current-Mode Voltage Reference for Harsh-Environment Operation Using CTAT Current Subtraction

Abstract

A new CMOS-only voltage reference, operating in current mode and leveraging subthreshold MOSFETs, is presented in this paper. In contrast to conventional solutions that sum PTAT and CTAT currents to provide a constant voltage reference, the proposed design introduces a zero temperature coefficient current by subtracting two CTAT currents—representing a key design novelty. Moreover, the presented approach does not use any trimming scheme to generate the output voltage.By eliminating bulky Bipolar Junction Transistors (BJTs), the circuit significantly reduces both area and power consumption while retaining robust performance in harsh environments over a temperature range from −20°C to 150°C. Fabricated in TSMC 130-nm CMOS technology, it delivers an output voltage near 610 mV with a measured temperature coefficient (TC) ranging from 188 ppm/°C to 212 ppm/°C across different chips. Owing to its current-mode operation, the voltage reference level can be readily adjusted through the decoder’s inputs, providing flexibility for a variety of applications. Measurement results confirm a power supply rejection (PSR) of −73 dB and a quiescent current of 3.2  $\mu $ A from a 1.2 V supply, making this trimless voltage reference an attractive option for compact, low-power systems.