A 0.5 V, 1 nA Switched Capacitor PTAT Current Reference Circuit

Abstract

This paper presents a low voltage, low power Proportional to Absolute Temperature (PTAT) current reference circuit. Switched capacitor is used instead of a large resistor, which in turn reduces the area of the circuit and makes the circuit less process sensitive. The proposed circuit has been designed using UMC 65 nm CMOS technology and simulated in Cadence Virtuoso. It generates a reference current (I<inf>ref</inf>) of 1 nA at 0.5 V supply voltage (V<inf>dd</inf>) at room temperature (27°C) and follows PTAT characteristics in the temperature range of -10°C to 80°C. The total power consumption of the circuit is as low as 1.5 nW. The supply voltage sensitivity of I<inf>ref</inf> is 2.7 %/V, which shows that the proposed circuit is less sensitive to supply voltage variations. Index Terms - Low voltage, Low power, PTAT current, Switched capacitor. © 2019 IEEE.