CMOS preamplifier with high linearity and ultra low noise for x-ray spectroscopy
- Brookhaven National Lab., Upton, NY (United States)
- Politecnico di Bari, Orabona (Italy)
We present an ultra low noise charge preamplifier suitable for small capacitance (200M), low leakage current solid state detectors. A self adaptive bias circuit for the MOS feedback device establishes the static feedback resistance in the G{Omega} range while tracking the threshold variations and power supply and temperature fluctuations. The linearity of the gain versus input charge has been improved by means of a voltage divider between the output of the charge-sensitive amplifier and the source of the feedback transistor. With the preamplifier alone, we measure a room-temperature equivalent noise charge (ENC) of 9 e{sup -} rms at 12 usec shaping time. When coupled to a cooled detector a FWHM of 130 eV is obtained at 2.4 usec shaping, corresponding to an ENC of 16 e{sup -} rms. This is the best reported resolution obtained with a CMOS preamplifier. The circuit has good linearity (< 0.2%) up to 1.8 W. Since the preamplifier`s ENC is limited by flicker noise, we fabricated the circuit in two 1.2um CMOS technologies. Device measurements allow us to compare the 1/f noise behavior of each foundry. In addition to the preamplifiers, a 1 us shaper and a 50{Omega} output driver are included on the die.
- OSTI ID:
- 512950
- Report Number(s):
- CONF-961123-; TRN: 97:014011
- Resource Relation:
- Conference: Institute of Electrical and Electronic Engineers (IEEE) nuclear science symposium and medical imaging conference, Anaheim, CA (United States), 2-9 Nov 1996; Other Information: PBD: 1996; Related Information: Is Part Of 1996 IEEE nuclear science symposium - conference record. Volumes 1, 2 and 3; Del Guerra, A. [ed.]; PB: 2138 p.
- Country of Publication:
- United States
- Language:
- English
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