Title :
Towards direct biochemical analysis with weak inversion ISFETs
Author :
Shepherd, Leila ; Townazou, C.
Author_Institution :
Dept. of Electr. & Electron. Eng., Imperial Coll., London, UK
Abstract :
A weak inversion region is shown to exist in ISFET sensors. It is therefore proposed that the ISFET and its ChemFET and EnFET 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. The first order temperature dependence of biochemical translinear circuits is greatly reduced from that of voltage-mode circuits. 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 4 decades. This paper demonstrates an important and necessary step towards biochemical VLSI.
Keywords :
VLSI; biochemistry; biomedical equipment; ion sensitive field effect transistors; patient monitoring; ChemFET; EnFET; biochemical VLSI; biochemical analysis; biochemical translinear principle; drain current; hydrogen ion; low-power current-mode input stage circuit; temperature dependence; voltage-mode circuits; weak inversion ISFET sensors; Biochemical analysis; Biomedical engineering; Biomedical monitoring; Biosensors; Chemicals; Circuits; Electrodes; Hydrogen; Insulation; Voltage;
Conference_Titel :
Biomedical Circuits and Systems, 2004 IEEE International Workshop on
Print_ISBN :
0-7803-8665-5
DOI :
10.1109/BIOCAS.2004.1454143
