Re-Usable 180nm Cmos Dosimeter Based On A Floating Gate Device

A rad-hard monolithic dosimeter has been designed and simulated in a standard 180 nm CMOS technology. The radiation sensor (C-sensor) is based on a floating gate MOS discharge principle. The output current is processed by a current-to-voltage (I-to-V) interface and then converted by a 5bit flash ADC. The dosimeter is re-usable (FG is recharged) and in this first version can detect a dose up to 1krad(Si) with a resolution of 30rad(Si), over process and temperature variations (0 to 85 degrees C). The ADC allows easy further signal processing for calibration, averaging, etc. The power consumption of C-sensor plus I-to-V interface is less than 2mW from a single 5 V power supply, while the ADC consumes 160mW. The overall layout area is less than 0.25mm(2). The Radiation Hardened By Design (RHBD) approach guarantees that the absorbed dose does not modify the performance of the mixed-signal circuitry.