Title :
A Low Noise CMOS Preamplifier Operating at 4.2 Kelvin
Author :
Kleine, U. ; Bieger, J. ; Seifert, H.
Author_Institution :
Siemens AG, Corporate Research and Development, ZFE BT ACM 23, Otto-Hahn-Ring 6, 8000 Munich 83
Abstract :
A low noise CMOS readout preamplifier operating at liquid helium temperatures for measuring human biomagnetic fields is described. The input of the folded cascode amplifier can be attached directly to a low impedance SQUID output (Superconducting QUantum Interference Device). Despite the occurrence of the kink effect in MOS transistor charcteristics at 4.2 Kelvin, no abnormal operation has been observed. An equivalent noise voltage density of 0.3 nV/¿Hz at 500 kHz has been measured. with such a preamplifier circuit the expensive shielding currently used in diagnosis systems can be simplified drastically.
Keywords :
Anthropometry; Biomagnetics; Helium; Humans; Kelvin; Noise measurement; Preamplifiers; SQUIDs; Superconducting device noise; Temperature measurement;
Conference_Titel :
Solid-State Circuits Conference, 1993. ESSCIRC '93. Nineteenth European
Conference_Location :
Sevilla, Spain
Print_ISBN :
2-86335-134-X
