A Poly Resistor Based Time Domain CMOS Temperature Sensor with 9b SAR and Fine Delay Line

Abstract

This paper presents a new type of time domain CMOS temperature sensor with a 9b successive approximation register (SAR) control logic and a fine delay line. We adopted an N-type poly resistor as the sensing element for temperature linearity. The chip was implemented in a standard 0.18 m 1P6M bulk CMOS process with general V-TH transistors and the active die area was 0.432 mm(2). The temperature resolution was 0.49 degrees C and the temperature error was from -1.6 to +0.6 degrees C over the range of 0 to 100 degrees C after two-point calibration. The supply voltage sensitivity was 0.085 degrees C/mV. The conversion rate was 25kHz and the energy efficiency was 7.2 nJ/sample.