Ultralow power CMOS cells for temperature sensors

Abstract

Temperature sensors and voltage references require cells that generate both PTAT (Proportional To Absolute Temperature) and NTC (Negative Temperature Coe±cient) voltages. We present a novel theoretical approach based on a quasi-constant current to obtain these voltages in standard CMOS technology using no resistors. A test circuit was fabricated in a 0:8 ¹m CMOS process. We performed measurements in a 305 K to 375 K temperature range which verify the expected results. The circuit draws under 50 nA from a 1.6 V to 3.0 V supply.