Radiation Hardened Digital to Analog Converter

ABSTRACT:Data transmission in communication systems, RADARs, satellite systems, and other military devices are dominated by analog data conversion. These high performance digital to analog converters (DAC) exceed 3Gsps with 12 bits of resolution and are readily available in the commercial marketplace, but they lack the radiation hardness required to support military satellite applications. Trusted Semiconductors Solutions has partnered with e2v, a proven commercial supplier of high performance data converters, to provide us access to DAC intellectual property. We have selected a commercial DAC that exceeds the performance requirements of this program and is well suited to hardening. The steps we will execute to harden the DAC include performing a radiation hardening assessment, retargeting the foundry technology, analyzing the radiation performance and implementing mitigation techniques. The technology we are targeting for the rad-hard DAC is a silicon germanium (SiGe) 180nm Bi-CMOS on Silicon-on-Insulator (SOI) process with 280GHz Fts. The resulting rad-hard DAC will have 12-bit resolution, operate at 2Gsps, SNR of >70dB and a SFDR >80dB. It will operate at TID >1Mrad(Si), SEU 1x1010 rad(Si)/s and DRS >1x1012 rad(Si)/s. This rad-hard DAC will be optimized for space based MILSATCOM and GPS applications.BENEFIT:Execution of this program provides the Air Force with a state-of-the art QML rad-hard DAC for space based MILSATCOM and GPS applications. Successful completion of Phase I and Phase II results in the delivery of a prototype radiation hardened Digital to Analog Converters. This 12-bit, radiation hardened DAC will have a sampling rate of 2Gsps, a signal to noise ratio of 70dB and spurious free dynamic range of 80DB. The DAC design and simulation work will be completed in Phase I, with the final GDSII database ready for fabrication. In Phase II, we will manufacture the DAC and test/characterize the prototype devices for performance, radiation hardness and reliability. Prototype devices will be fabricated on-shore and parts assembled in a ceramic, hermetically sealed LGA package suitable for space flight. Full-scale radiation characterization testing will be performed including total ionizing dose testing with a Cobalt-60 source, heavy-ion testing for single event effects and latch-up, proton and neutron testing. Product upgrade and MIL-PRF-38535 space-level QML qualification testing will be performed in Phase III.