Single-pair Ethernet PHY Offers Ultra-low TC10-compliant Sleep Current, Functional Safety Ready

By Tiera Oliver

Associate Editor

Embedded Computing Design

July 28, 2020

News

Microchip's LAN8770 is an IEEE 802.3bw-compliant 100BASE-T1 PHY in a 5 x 5 mm package for space-constrained automotive applications.

Microchip Technology announced the LAN8770, an OPEN Alliance TC10 sleep standard Ethernet physical layer transceiver (PHY). According to the company, the device features the industry’s lowest sleep current, less than 15 µA, which is around four times lower than other available devices.

The LAN8770 is a compact, single-port 100BASE-T1 Ethernet PHY compliant with the IEEE 802.3bw-2015 specification and available in a 5 x 5 mm or 6 x 6 mm wettable-flanks QFN package. The small package is ideal for space-constrained applications such as the infotainment head unit, telematics modules, or Advanced Driver Assistance Systems (ADAS).

According to the company, the device provides 100 Mbps transmit and receive capability over a single Unshielded Twisted Pair (UTP), exceeds automotive electromagnetic interference requirements and is Grade 1 (-40°C to +125°C) automotive AEC-Q100 qualified. In addition, the LAN8770 is Microchip Functional Safety Ready; it is designed to simplify customers’ end-product ISO26262 safety certification with the support of specialized hardware safety features, Failure Modes, Effects, and Diagnostic Analysis (FMEDA) and safety manual.

The LAN8770M and LAN8770R support communication with an Ethernet MAC via standard MII/RMII and MII/RMII/RGMII interfaces. An optional 125 MHz or 50 MHz reference clock output is also provided for RGMII and RMII applications, often enabling elimination of an external reference clock.

“Typically, an automotive module can only consume 100 microamps maximum in sleep (battery) mode so, if the PHY alone consumes north of 50 microamps, additional circuitry is required to avoid exceeding the target power budget,” said Charles Forni, vice president of Microchip’s USB and Networking business unit. “Often, applications add an additional wire or CAN bus just to enable and disable the power. Our PHY avoids such a need, minimizing components, installation and cost.”

Per the company, the LAN8770 EtherGREEN energy efficiency technology provides low-power operation along with ultra-low-power sleep and wake-up modes. Power efficiency is further enhanced with optional integrated linear regulator and Microchip’s flexPWR technology for variable xMII and input/output supply voltages, providing flexible design options, and more opportunities to save power.

Advanced PHY diagnostics provide the user with troubleshooting capabilities through Microchip’s integrated LinkMD cable diagnostic system designed to detect cable defects, shorts, or opens. The device also provides a receiver Signal Quality Indicator (SQI), over-temperature and under-voltage protection, and status interrupt support along with loopback and test modes.

The PHY family is backed by Microchip’s free LANCheck online design service that reviews customer designs, ensuring that suitable design practices are used. AUTOSAR, Linux, and RTOS software drivers are also available.

A separate 100BASE-T1 to 100BASE-TX Media Converter evaluation kit is available now. A 100BASE-T1 daughter card evaluation board is available for use with Microchip’s ATSAMV71-XULT Xplained Ultra microcontroller kit as well as the SAMA5D3-EDS microprocessor kit.

The new Ethernet PHY family includes two devices: the LAN8770M (MII/RMII) and LAN8770R (MII/RMII/RGMII) in 5 x 5 mm 32-pin and 6 x 6 mm 36-Pin QFN packages, respectively. Both devices are available for purchase.

For more information, visit: www.microchip.com.

Tiera Oliver, Associate Editor for Embedded Computing Design, is responsible for web content edits, product news, and constructing stories. She also assists with newsletter updates as well as contributing and editing content for ECD podcasts and the ECD YouTube channel. Before working at ECD, Tiera graduated from Northern Arizona University where she received her B.S. in journalism and political science and worked as a news reporter for the university’s student led newspaper, The Lumberjack.

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