TY - JOUR
T1 - Noise Performance of a Regulated Cascode Transimpedance Amplifier for Radiation Detectors
AU - Oliveira, Luís Augusto Bica Gomes de
AU - DEE Group Author
PY - 2012/1/1
Y1 - 2012/1/1
N2 - A low noise transimpedance amplifier (TIA) is used in radiation detectors to transform the current pulse produced by a photo-sensitive device into an output voltage pulse with a specified amplitude and shape.We consider here the specifications of a PET (positron emission tomography) system. We review the traditional approach, feedback TIA, using an operational amplifier with feedback, and we investigate two alternative circuits: the common-gate TIA, and the regulated cascode TIA. We derive the transimpedance function (the poles of which determine the pulse shaping); we identify the transistor in each circuit that has the dominant noise source, and we obtain closed-form equations for the rms output noise voltage. We find that the common-gate TIA has high noise, but the regulated cascode TIA has the same dominant noise contribution as the feedback TIA, if the same maximum transconductance value is considered. A circuit prototype of a regulated cascode TIA is designed in a 0.35 m CMOS technology, to validate the theoretical results by simulation and by measurement.
AB - A low noise transimpedance amplifier (TIA) is used in radiation detectors to transform the current pulse produced by a photo-sensitive device into an output voltage pulse with a specified amplitude and shape.We consider here the specifications of a PET (positron emission tomography) system. We review the traditional approach, feedback TIA, using an operational amplifier with feedback, and we investigate two alternative circuits: the common-gate TIA, and the regulated cascode TIA. We derive the transimpedance function (the poles of which determine the pulse shaping); we identify the transistor in each circuit that has the dominant noise source, and we obtain closed-form equations for the rms output noise voltage. We find that the common-gate TIA has high noise, but the regulated cascode TIA has the same dominant noise contribution as the feedback TIA, if the same maximum transconductance value is considered. A circuit prototype of a regulated cascode TIA is designed in a 0.35 m CMOS technology, to validate the theoretical results by simulation and by measurement.
KW - transimpedance amplifiers
KW - circuit theory
KW - positron emission tomography
KW - Amplifiers
KW - radiation detectors
U2 - 10.1109/TCSI.2011.2180449
DO - 10.1109/TCSI.2011.2180449
M3 - Article
SN - 1057-7122
VL - 59
SP - 1841
EP - 1848
JO - Ieee Transactions On Circuits And Systems I-Regular Papers
JF - Ieee Transactions On Circuits And Systems I-Regular Papers
IS - 9
ER -