Title :
A wideband ultra-low-current on-chip ammeter
Author :
Lu, Junjie ; Holleman, Jeremy
Author_Institution :
Univ. of Tennessee, Knoxville, TN, USA
Abstract :
A high-bandwidth ultra-low-current measurement circuit is presented in this paper. The circuit is capable of measuring an on-chip 75 fA current at a bandwidth up to 1 kHz with a noise floor of 0.235 fArms/√Hz. A low leakage reset scheme is utilized to improve the precision. Nested auto-zeroing combined with modified correlated double sampling is employed to mitigate the error due to various circuit imperfections. Noise analysis is carried out and “capacitive noise matching” is proposed to minimize the noise floor. The circuit is also capable of digitizing the measured current and streaming the data through a serial interface. The measurement circuit occupies 0.065 mm2 of active silicon area in a 90 nm CMOS process and consumes 147 μW from 2.5 V and 1V supplies.
Keywords :
CMOS integrated circuits; ammeters; integrated circuit measurement; noise; CMOS process; active silicon area; capacitive noise matching; circuit imperfection; current 25 fA; high-bandwidth ultra-low-current measurement circuit; leakage reset scheme; modified correlated double sampling; nested auto-zeroing; noise analysis; noise floor; on-chip 75 fA current; power 147 muW; serial interface; size 90 nm; voltage 1 V; voltage 2.5 V; wideband ultra-low-current on-chip ammeter; Bandwidth; Current measurement; Floors; Logic gates; Noise; Noise measurement; Switches;
Conference_Titel :
Custom Integrated Circuits Conference (CICC), 2012 IEEE
Conference_Location :
San Jose, CA
Print_ISBN :
978-1-4673-1555-5
Electronic_ISBN :
0886-5930
DOI :
10.1109/CICC.2012.6330668