SEL-Oriented Rad-Hard Strategy and Characterization of the XCR4C ASIC for X-ray CCD Applications

We report in this work the SEL hardness assurance test (HAT) for the XCR4C ASIC, which is a rad-hard fullfunction four-channel correlated double sampling (CDS) ASIC targeting the readout of X-ray CCDs for applications in the fields of X-ray spectroscopy, imaging and timing observations. The ASIC is implemented in a novel differential switchedcapacitor architecture, which makes it high linear, low power, immune to commom-mode noise and interferences as well as easy configurable. Some SEL-oriented rad-hard strategies are adopted to combat the harsh low-earth-orbit (LEO) space environment, among which we describe in detail the pesudo double guard ring (PDGR) layout technique and the process hardness method. The XCR4C ASIC was fabricated with AMS 0.35 μm 2P4M bulk CMOS process with an epitaxial layer and occupies a chip area of 3.47×1.84 mm
²
. The HAT was carried out at the Heavy Ion Research Facility in Lanzhou (HIRFL), where the ASIC was irradiated by
¹⁸¹
Ta
³¹⁺
ions with a linear energy transfer (LET) in silicon up to 81.35 MeV-cm
²
/mg. The results showed that till to a total fluence as high as 1.68×107 ions/cm
²
, not a single latchup was monitored, and the performance degradations after irradiation were negligible.