Title :
A low noise CMOS preamplifier for femtoampere current detection
Author :
Zhang, Ming ; Llaser, Nicolas ; Mathias, Herve
Author_Institution :
MiNaSys, Univ. of Paris XI, Orsay
Abstract :
This paper presents a low noise CMOS preamplifier for femtoampere detection. Based on a classical charge amplifier, a ping-pong technique is proposed to reset the charge amplifier, keeping the preamplifier stable even in a strong parasitic DC current. With a low reset frequency, the undesired folding noise is greatly reduced and the signal-to-noise ratio (SNR) at the output can be kept almost constant. The simulation results show that using the proposed preamplifier, the output SNR can still be 72 for an input current of 200 fA among a parasitic DC current of 100 pA. The dynamic range is observed over 120 dB.
Keywords :
CMOS integrated circuits; electric current measurement; integrated circuit noise; low noise amplifiers; charge amplifier; femtoampere current detection; input current; low noise CMOS preamplifier; parasitic DC current; ping-pong technique; signal-to-noise ratio; Current measurement; Dynamic range; Feedback; Low-frequency noise; Low-noise amplifiers; Noise reduction; Preamplifiers; Resonant frequency; Rotation measurement; Signal to noise ratio;
Conference_Titel :
Circuits and Systems, 2008. ISCAS 2008. IEEE International Symposium on
Conference_Location :
Seattle, WA
Print_ISBN :
978-1-4244-1683-7
Electronic_ISBN :
978-1-4244-1684-4
DOI :
10.1109/ISCAS.2008.4541862
