Gain-Bandwidth Product Compensation Technique by 16-Unit Tail Current Control for a Radiation Tolerant Preamplifier With 0.9% Amplitude Drop up to 5 Mrad

This article presents a self-compensated charge-sensitive amplifier (CSA) for total ionizing dose (TID) effects, which directly compensates for the nonlinearity characteristic of the preamplifier, caused by radiation. The proposed circuit is operated by monitoring on amplitude degradation of a replicated CSA from a constant pulse and compensating the main CSA from the gain bandwidth product (GBWP) equation with current steering DAC control. The proposed technique was evaluated under a gamma-ray irradiation environment using Cobalt-60 with an activity of 490 kCi at Korea Atomic Energy Research Institute (KAERI) in Korea and provided a linear output with an amplitude degradation of 0.9%. In contrast, a noncompensated CSA showed a 70% decrease in amplitude after irradiation exposed to up to 5 Mrad (SiO2). The proposed technique was fabricated in a 180-nm standard BiCMOS technology. This direct compensation approach offers a promising solution to reduce radiation effects on the preamplifier for applications of radiation-hardened electronics.