Single-pair Ethernet tranceivers suite automotive links up to 40m

Single-pair Ethernet is also being used in avionics, robotics and automation, it said.

“For interoperability across industries, LAN887x PHYs are designed to be compliant with IEEE 802.3bp for the 1000BASE-T1 specification, and IEEE 802bw-2015 for the 100BASE-T1 specification*,” according to the company. “Microchip has collaborated with the University of New Hampshire to create the development test platform for 1000BASE-T1 conformance. For many automotive and industrial applications that operate in harsh environments and need to withstand extreme temperatures, these devices are also designed to be ISO 26262 functional safety ready with ASIL B classification.”

Three base parts are being introduced.

All support 15m of unshielded balanced copper cabling with up to four in-line connectors along it (IEEE 802.3bp 1000BASE-T1 ‘link segment Type A’) :

• LAN8870 supports:
  SGMII MAC interface
  RGMII MAC interface
  LAN8870B only – 1000BASE-T1 40m (Type B) cables
• LAN8871 supports:
  RGMII MAC interface
• LAN8872 supports:
  GMII MAC interfaces

“Based on the expected customer base Microchip has initially chosen to grade only the most full-featured device, LAN8870, as Type B” for longer cables, the company told Electronics Weekly. “In addition, the applications presented by early Type B customers often include harsh environmental requirements – examples include agriculture and construction equipment – thus, the LAN8870B device is available only in wide temperature, automotive quality level.”

All of them support IEEE 1588-2019, 802.1AS-2020 and OPEN Alliance TC10, come in -40 to +105°C (Grade 2 Automotive) or -40 to 85°C (industrial) versions, and have 48pad VQFN packaging with wettable flanks – OPEN Alliance TC10 sleep and wake-up allows a maximum of 16µA stand-by consumption.

“The LAN887x is TSN (Time Sensitive Networking) ready, supporting IEEE802.1AS-2020 and IEEE1588-2019 precision clock synchronisation protocol for real time Ethernet networking,” said Microchip.

Diagnostics include cable fault detection, signal quality indication, link down and errors, built in self-test, temperature monitoring and voltage monitoring. There is also an optional integrated linear regulator – Electronics Weekly has asked how the latter is indicated in the part number.

Find the LAN8870 product page here

*it is possible that only LAN8870 and LAN8870B support 100BASE-T1 – Electronics Weekly has asked for clarification. Data sheets are not publicly available