Active EtherCAT slave controller with integrated PHY
The LAN9255-V/ZMX020 is an EtherCAT slave controller from Microchip Technology, integrating a 100BASE-TX PHY per IEEE 802.3 and USB 2.0 — so one chip handles the fieldbus interface and the physical layer without an external PHY. The 128-TQFP Exposed Pad (14x14 mm) package provides a thermal path through the exposed paddle to the PCB copper plane — the datasheet's recommended footprint includes a thermal via array under the pad to keep junction temperature within limits under full traffic load.
Interface selection and protocol support
Three host interface options are available: a parallel bus for legacy MCUs, RMII for reduced-pin-count Ethernet MAC connections, and USB 2.0 for direct connection to a host processor's USB port — the RMII interface saves eight pins compared to a full MII, freeing GPIO on the controller for other functions. The integrated 100BASE-TX PHY meets IEEE 802.3, so the BOM does not need a separate Ethernet transceiver — this reduces the PCB footprint and eliminates the magnetics routing between discrete PHY and MAC.
The Tray packaging is standard for volume assembly; no additional moisture-sensitive handling beyond the MSL level printed on the reel label.
Sourcing and availability
No single-source risk here: Microchip maintains multiple fab and assembly sites for this product line, and the Active lifecycle means no last-time-buy pressure for existing designs.