Typically SRAM-based FPGAs when used in space, can experience the problem of changes to the information written in the SRAM due to the effects of radiation, says NEC.

For example, radiation can cause an electrical charge in the semiconductor substrate. As a result, a failure occurs to the SRAMs in FPGAs that record information based on the amount of charge, causing a change in the circuit configuration.

NEC claims its NanoBridge technology enables a tenfold improvement over the power efficiency of conventional FPGAs as well as providing them with high radiation tolerance.

NEC has conducted an operation demonstration jointly with the Japan Aerospace Exploration Agency (JAXA), using the newly developed NB-FPGA in a tough radioactive terrestrial environment.

As a result, it has confirmed that the ON and OFF states of the NanoBridge remain unchanged, whether radiation is delivered or not.

Yuichi Nakamura, general manager at NEC Research Laboratories, writes:

Based on the result, NEC expects that the NanoBridge will be able to reduce the frequency of errors caused by radiation to one percent or less and contribute to the creation of an LSI that offers high radiation tolerance and ultra-low power consumption simultaneously.

The next step is to validate the NB-FPGA by incorporating it in the Satellite Technology Demonstration 1, which will be launched in FY2018.

The NanoBridge uses the cross-link of metal atoms in a solid electrolyte to place the signals into the ON or OFF state (See Figure.1 right).

The ON or OFF state is maintained even after voltage is released. The cross-link created by metal atoms in the NanoBridge is free from the impact of electrical charges generated by the delivery of radiation.

Accordingly, the possibility of rewriting is extremely remote in the circuit of NB-FPGA, even in a space environment that is exposed to a large amount of radiation, which improves reliability, says NEC.

In the Innovative Satellite Technology Demonstration 1, a demonstration experiment of compressing and transmitting camera-captured images through the NB-FPGA will be carried out in a harsh environment.

Image:Operation mechanism of NanoBridge (left), NB-FPGA chip (right)

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NEC develops reliable FPGAs for space travel - Electronics Weekly - Electronics Weekly