A CMOS 12-Bit 3MS/s Rad-Hard Digital-to-Analog Converter Based on a High-Linearity Resistor String Poly-Matrix

• Published in: Chips Vol. 3; no. 2; pp. 129 - 152
• Main Authors: Calligaro, Cristiano, Gatti, Umberto
• Format: Journal Article
• Language: English
• Published: MDPI AG 08.05.2024
• Subjects: DAC; data converter; rad-hard; RHBD; SEE; TID
• ISSN: 2674-0729; 2674-0729
• DOI: 10.3390/chips3020006

This work presents a rad-hard 12-bit 3 MS/s resistor string DAC for space applications. The converter has been developed using rad-hardened techniques both at architecture and layout levels starting from a conventional topology. The design considers the different effects of the radiation that could damage the circuits in space environments. The DAC has been developed and integrated a standard CMOS 0.13 μm technology by IHP, using RHBD techniques. Low Earth Orbit (LEO) requires a TID value of around 100 krad (Si), according to the expected length of the mission. The temperature range is between −55 °C and 125 °C. The DAC power budget is similar to that of terrestrial applications. The measured INL (Integral Non-Linearity) and DNL (Differential Non-Linearity) are better than 0.2 LSB, while the ENOB (Effective Number Of Bits) at a 3 MS/s clock exceeds 9.7 bits while loading a 10 pF capacitor. The DAC has been characterized under radiation, showing a fluctuation in the analog output lower than 2 LSB (mainly due to measurement uncertainty) up to 500 krad (Si). Power consumption shows a negligible increase, too. A 10-bit version of the same DAC as the downscaled 12-bit one has been developed as well.