Analysis and Comparison of Rad-Hard Ring and LC-Tank Controlled Oscillators in 65 nm for SpaceFibre Applications

Abstract

This work presented a comparison between two Voltage Controlled Oscillators (VCOs) designed in 65 nm CMOS technology. The first architecture based on a Ring Oscillator (RO) was designed using three Current Mode Logic (CML) stages connected in a loop, while the second one was based on an LC-tank resonator. This analysis aimed to choose a VCO architecture able to be integrated into a rad-hard Phase Locked Loop. It had to meet the requirements of the SpaceFibre protocol, which supports frequencies up to 6.25 GHz, for space applications. The full custom schematic and layout designs are shown, and Single Event Effect simulations results, performed with a double exponential current pulses generator, are presented in detail for both VCOs. Although the RO-VCO performances in terms of technology scaling and high-integration density were attractive, the simulations on the process variations demonstrated its inability to generate the target frequency in harsh operating conditions. Instead, the LC-VCO highlighted a lower influence through Process-Voltage-Temperature simulations on the oscillation frequency. Both architectures were biased with a supply voltage of 1.2 V. The achieved results for the second architecture analyzed were attractive to address the requirements of the new SpaceFibre aerospace standard.

Diagnosis of Faults Induced by Radiation and Circuit-Level Design Mitigation Techniques: Experience from VCO and High-Speed Driver CMOS ICs Case Studies

“…In [36,37], an LC-Tank-based VCO compliant with the SpaceFibre protocol for the space environment is designed. The diagnosis of radiation effects is performed by a simulation-before-test, and the charge injection, due to particle hitting, is implemented with the classical double exponential shape [21][22][23].…”

“…Moreover, the impact of the charge injection depends on signal status, thus the test bench should take it into account; once a sensitive node is found, it is necessary to investigate the different effects that an ionising particle has during waveform shape. For the implemented architecture, the most sensitive nodes are the outputs of the oscillator because varactors are directly connected to them [21,22,36,37], as shown in Figure 4. Figures 5 and 6 show the effects generated by a particle strike on the frequency of the most sensitive node of the VCO.…”

Design and analysis of 7-stage MOS current mode logic power gated MOSFETs in current starved voltage-controlled oscillator for the phase locked loop application

“…A ring oscillator is another type of oscillator which is used due to its simple and digital nature, a ring oscillator can be easily integrated into IC designs with minimal additional complexity and cost [1]. The design of ring and LC oscillator using current mode logic and tank resonator for the space fiber application provide better analysis on the performance [2]. The advancement of rapid and effective technology heavily depends on high-speed devices.…”

Recent Trends on Applications of Electronics Pervading the Industry, Environment and Society

“…The Special Issue is characterized by 13 original research papers [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ] that we briefly introduce in the following.…”

“…The second paper [ 2 ] is entitled “Analysis and Comparison of Rad-Hard Ring and LC-Tank Controlled Oscillators in 65 nm for SpaceFibre Applications”, written by D. Monda et al from the University of Pisa and by INFN (the Italian National Institute for Nuclear Physics).…”