Ethernet Gives Space Applications Higher Data Rates

Article By : M. Di Paolo Emilio

Microchip has developed a space-qualified Ethernet communication solution based on a Commercial Off-the-Shelf (COTS) for space applications.

Microchip’s first space-qualified Ethernet transceiver offers the possibility of interoperability between satellites and other space vehicles, all based on a commercial off-the-shelf (COTS) solution. Applications range from launch vehicles to satellite constellations and space stations.

The increasing complexity of systems has led to the spread of distributed architectures. With distributed architectures, the selection of the connection bus is crucial to meet performance and reliability requirements. Ethernet is increasingly the choice in the aerospace field, with the aim of supporting higher data rates. The Ethernet protocol is also well known in the automotive and industrial markets, allowing some synergies between various space applications.

“Ethernet connectivity is selected as the main technology, for example, to connect modules of the deep space gateway program driven by NASA,” said Nicolas Ganry, manager of product marketing – aerospace, at Microchip.

“It is an international project where different nations, space industry participants and agencies will work to develop Ethernet solutions. Strong radiations robustness is required for such space missions; this is the main criteria to select the right solution. On top of that, for this mission a Gbit traffic solution is required in a ceramic package to achieve QMLV qualification level. That is another challenge to have this type of ceramic part with the same level of performances than plastic industrial parts. The VSC8541RT Microchip Ethernet transceiver provides superior radiation results while providing a high-performance solution in ceramic package at space grade qualification level,” said Ganry.

The working conditions of a spacecraft depend on where it is headed, so engineers carefully test and select the electronics part for each vehicle. Radiation is constant environmental issue. As waves or as particles, radiation can affect electronics in several ways.

“The space environment is exposed to radiation effects that have some impact on any electronic device,” Ganry said.

He listed the most common consequences of radiation:

SEL: single event latch-up, which is a high-current event that can destruct the electronic device.

TID: total ionizing dose effect, in which the accumulation of ions can lead to threshold shifts, device leakage, timing changes, and otherwise decreased functionality.

SEU: single event upset, in which a functional bit or several bits are upset, which can change the result of any electronic activity, up to…

…SEFI: which is functional interrupt of the device.

“A rad-tolerant electronic device is more robust than a commercial off-the-shelf (COTS) device, as it must be modified to support space applications. A rad-tolerant device is latch-up immune and non-destructive to radiation, supporting a dose rate between 30Krad to 100Krad. A full SEU effect characterization is done on the device in order to give the error occurrence and elements to mitigate an error upset when it happens,” said Ganry.

The new VSC8541RT transceiver is a single port Gigabit Ethernet PHY with GMII, RGMII, MII and RMII interfaces. The VSC8541RT is latch-up immune up to 78 MeV; TID has been tested up to 100 Krad. With the same radiant tolerance package, VSC8540RT, with a limited bitrate performance of 100 MB, is also available in qualified plastic and ceramic versions, offering performance and cost scalability for targeted missions (Figure 1).

Microchip’s EcoEthernet™ v2.0 technology supports IEEE 802.3az Energy-Efficient Ethernet (EEE) and power-saving features. VSC8541RT device optimizes power consumption and features a Wake-on-LAN (WoL) power management mechanism for bringing the PHY out of a low-power state using a designated magic packet.

Figure 1: Block diagram of VSC8541RT transceiver

In addition to the new sampling of Microchip’s VSC8541RT radiation-tolerant Ethernet transceiver, the company received the final qualification for the new SAM3X8ERT radiation-tolerant microcontroller. The radiation-resistant SAM3X8ERT MCU implements a system on chip (SoC) with the widely deployed Arm Cortex-M3 core processor, offering 100 DMIPS benefits from the same ecosystem as the industrial variant (Figure 2).

Figure 2: Block diagram of SAM3X8ERT radiation-tolerant microcontroller
Figure 2: Block diagram of SAM3X8ERT radiation-tolerant microcontroller

“Looking to less specific space solution is the trend to reduce development cost and improve design lead time for time-to-market improvements. Microchip’s SAM3XE8RT microcontroller with embedded Ethernet controller combined with the Ethernet transceiver VSC8541RT provides a fully proven Ethernet point to point solution for space application. On top of those key advantages, the Ethernet network – thanks to switch capabilities – can support high bandwidth distributed architecture demand for more and more high data rate space applications. Microchip is looking forward to extending space Ethernet rad tolerant system solutions in this direction in order to take full advantage of a proven, well-known technology.” Said Nicolas Ganry.

To support the design process and accelerate time to market, developers can use the commercial Arduino Due kit for SAM3X8ERT in conjunction with VSC8541EV evaluation boards for VSC8541RT. COTS-based space level processing provides the right performance and qualification level to meet evolving requirements, especially in low earth orbit and deep space applications.

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