Title :
A biochemical translinear principle with weak inversion ISFETs
Author :
Shepherd, Leila M. ; Toumazou, Chris
Author_Institution :
Dept. of Electr. & Electron. Eng., Imperial Coll. London, UK
Abstract :
A weak inversion region is shown to exist in ion-sensitive field effect transistor (ISFET) sensors. It is therefore proposed that the ISFET and its chemically sensitive (ChemFET) counterparts be used as translinear elements in the synthesis of novel biochemical input stages which perform real-time mathematical manipulation of biochemical signals. A Biochemical Translinear Principle using weakly inverted ChemFETs is presented. A low-power current-mode input stage circuit is presented as an application of the principle. This yields a linear relation between drain current and hydrogen ion concentration valid over four decades. This paper demonstrates an important and necessary step toward biochemical VLSI.
Keywords :
VLSI; biochemistry; chemical sensors; ion sensitive field effect transistors; ChemFET; biochemical VLSI; biochemical signal; biochemical translinear principle; chemically sensitive field effect transistor; chemically sensitive ion-sensitive field effect transistor; drain current; hydrogen ion concentration; ion-sensitive field effect transistor sensor; low-power current-mode input stage circuit; real-time mathematical manipulation; translinear element; weak inversion ISFET; weak inversion region; Biomedical monitoring; Biomembranes; Biosensors; Chemical and biological sensors; Chemical elements; Chemical technology; Circuits; FETs; Sensor arrays; Threshold voltage; CMOS; Chemically sensitive ion-sensitive field effect transistor (ChemFET); ISFET; low power; pH; weak inversion;
Journal_Title :
Circuits and Systems I: Regular Papers, IEEE Transactions on
DOI :
10.1109/TCSI.2005.857919
