Microchip Unwraps New 10BASE‑T1S ICs to Scale Edge Connectivity

Microchip recently announced a new set of wired single-pair Ethernet (SPE) chips. The set includes two 10BASE‑T1S physical medium dependent (PMD) transceivers and five highly integrated 10BASE-T1S serial endpoints.

The new transceivers and integrated endpoint devices may simplify zonal architectures in automotive and industrial use cases. 

Microchip designed the LAN8679 and LAN8680 transceivers to simplify Ethernet connectivity via the OPEN Alliance 3-pin (OA3P) Interface. The endpoints, the LAN8660X/1X/2X family, take the job further by integrating the protocol stack and providing a softwareless connection solution.

Key Features of the New SPE Chips

All parts connect to the network through a simple interface that requires only AC coupling capacitors and Ethernet magnetics (transformer), often integrated into the connector. They operate under the automotive 10BASE-T1S standard, delivering 10 Mbps communication speeds. All parts feature a multidrop topology, allowing (typically) eight or more devices to communicate over a single shared bus wire set.

They meet AEC-Q100 and ISO 26262 functional safety standards and operate in a -40°C to +125°C temperature range.

LAN8679 and LAN8680

The LAN8679 and LAN8680 are 10BASE-T1S single-pair PMD transceivers that use the OA3P interface between the transceiver and the MCU. The three OA3P pins are TX, RX, and energy detect (ED), which signals the host MCU to wake up. 

New Microchip LAN8679 and LAN8680. 

The LAN8680 adds system-basis chip (SBC) functionality with power management, wakeup/sleep control, and a watchdog. The two transceivers come in a small footprint 16-pin 3 mm x 4.5 mm QFN package.

LAN8660X, LAN8661X, and LAN8662X

The LAN8660X/1X/2X family comes as self-contained, complete remote control protocol (RCP) endpoints. That means the chip contains everything required to connect to a 10BASE-T1S network. No need for an Ethernet protocol stack or Ethernet-related software. That makes the chips ideal for smaller, less feature-rich peripheral devices. Microchip targets the LAN8660X for sensors and actuators, the LAN8661X for lighting and small displays, and the LAN8662X for microphones and speakers. The endpoints all come in a 32-pin 5 mm x 5 mm QFN package.

Distinctions in the LAN866xX family. 

While automotive electronics are the primary application for these devices, they also fit well in industrial automation, aerospace, defense, and robotics systems. The LAN8679, LAN8680, and LAN8660X/1X/2X are now available in sample quantities.

Reducing the Ethernet Overhead

Ethernet is a very powerful and nearly universal communications system. With that power, however, comes significant overhead that makes it difficult to implement in lower-powered systems. SPE is one of the new options for reducing overhead. Single pair uses a bespoke physical layer (PHY) that lets devices share cables, while traditional Ethernet requires a cable to a switch for each device. This reduces cable requirements and cuts cost and weight.

Multidrop capability lets multiple nodes share channels on the same cable, further reducing overhead. The higher software layers remain unchanged from standard 10BASE-T1, 100BASE-T1, and 1000BASE-T1.

Ethernet Endpoint Applications

10BASE-T1S is the latest automotive-oriented 10 Mbps Ethernet standard. It allows unshielded twisted-pair wiring for in-vehicle networks (IVN). Automotive and industrial equipment increasingly relies on a zonal computing architecture connected via Ethernet. A powerful central computer lies at the heart of zonal architecture. From there, a vehicle or industrial machine is divided into zones, each with local computing and smart application modules. Zonal gateways communicate with the central computer.

The new Microchip parts are designed to enable that communication topology. The endpoints, with an included protocol stack, connect to systems with low computing resources. The integrated PMD transceiver in the endpoints replaces the need for Ethernet physical layer (PHY) hardware in the devices. The transceivers connect to domain control computers or peripheral microcontrollers with enough power to include the PHY and protocol software. 

All images used courtesy of Microchip.