Open AccessDifferential pH‐sensitive sensor with DC electrode‐offset compensation
Author(s) -
Lee K.H.,
Lee D.,
Yoon J.,
Kwon O.,
Lee J.
Publication year - 2017
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
eISSN - 1350-911X
pISSN - 0013-5194
DOI - 10.1049/el.2016.3330
Subject(s) - electrode , offset (computer science) , dc bias , compensation (psychology) , materials science , optoelectronics , electrical engineering , electronic engineering , computer science , voltage , engineering , chemistry , psychology , psychoanalysis , programming language
A pH‐sensitive sensor with a differential mode was developed to detect surface charges accumulated on the ion‐sensitive layer. The device accurately monitors the relative pH value using the modified instrumentation amplifier with the DC electrode‐offset compensation. The readout voltage is digitalised with the current‐starved ring oscillator. The sensor achieves the DC offset compensation of 22.5 dB and the oscillating pH sensitivity of 1.3 MHz/pH. The feasibility of the sensor is demonstrated to monitor the hydrogen ion concentration comparing the oscillation frequency at differential mode with that at single mode.