High Resolution CMOS Frequency-to-digital Converter for a Fine Dust Sensor using a MEMS Resonator

• Published in: Journal of semiconductor technology and science Vol. 22; no. 3; pp. 168 - 176
• Main Author: Moon, Hyunwon
• Format: Journal Article
• Language: English
• Published: 대한전자공학회 01.06.2022
• Subjects: 전기공학; CMOS; oscillator; 38453; Delay-locked loop (DLL); MEMS resonator; Fine dust sensor; high resolution
• ISSN: 1598-1657; 2233-4866
• DOI: 10.5573/JSTS.2022.22.3.168

A high resolution, low power CMOS oscillator and frequency-to-digital converter for a fine dust sensor using a MEMS resonator is proposed. The proposed frequency-to-digital converter is realized based on dual-loop hybrid delay-locked loop to distinguish fine frequency variations according to very small fine dust concentrations, and simultaneously applied binary and square search algorithms to obtain accurate digital codes indicating frequency changes. An oscillator and frequency-todigital converter for a fine dust sensor is implemented using the 0.18-μm CMOS process. The core size of the fabricated MEMS oscillator and frequency-to-digital converter is 0.9 mm2 and consumes about 16 mW of power at 1.8 V supply voltage. The proposed frequency-to-digital converter covers the input frequency range of 1.7 GHz to 2.3 GHz with 1 bit resolution of about 3 MHz. KCI Citation Count: 0