This paper presents a radiation-hardened-by-design (RHBD) preamplifier that utilizes a self-reset technique when the preamplifier becomes saturated. The proposed RHBD preamplifier comprises the charge-sensitive amplifier (CSA) part with the self-reset circuit and total ionizing dose (TID) effects compensation part. The CSA part consists of a comparator, a feedback switch, and a trigger circuit. The trigger circuit generates a pulse with sufficient duration to reset the feedback capacitor when the CSA becomes saturated. TID effects compensation part utilizes a binary current source to compensate TID effects in the CSA. The current source control unit detects the operating point of the OPAMP and generates appropriate signals to control the current source switches. The proposed circuit was fabricated using general-purpose 0.18 μm CMOS technology, and verified through an irradiation test up to 231 kGy (SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>) at a rate of 10.46 kGy/h.