28 nm Charge sensitive preamplifier using 1 GΩ dual PMOS feedback resistor operating in the weak inversion region

We are reporting for the first time a novel design methodology for a small size, low power, charge sensitive preamplifier operating in the weak inversion region using 28 nm CMOS technology. This preamplifier will be suitable for room temperature semiconductor nuclear radiation detectors needed for portable applications, medical imaging and future nano-scale medical instruments. The weak inversion MOSFET region allows to design a GΩ feedback resistor using one or two PMOS transistors with almost negligible size and power consumption. This GΩ resistor will enhance the operation of the preamplifier and maximize charge collection. The total size of the reported preamplifier is 55.25 μm2 and its power consumption is 13nW (including current source).