Device identity and dual-supply rail
The LAN9514-JZX is a USB 2.0 to Ethernet bridge controller integrating a 10/100 Base-T/TX PHY, handling the protocol conversion between a USB host and an RJ-45 Ethernet port without an external MAC or PHY chip. It requires two supply rails — 1.8 V for the core logic and 3.3 V for the I/O and PHY — so the board design must budget for both voltages, typically from a dual-output regulator or two separate LDOs. The 288 mA supply current figure covers the full operating state with both USB and Ethernet active; the actual draw varies with link speed and traffic, but this is the number to use for the worst-case thermal budget.
Package footprint and thermal management
Housed in a 64-VFQFN with an exposed pad (supplier device package 64-QFN 9x9 mm), the part requires a thermal via array under the pad to conduct heat into the PCB ground plane — without it, the junction temperature rises above the 70°C ambient ceiling in a confined enclosure.
Lifecycle and compliance standing
The part ships in Tray packaging, which is the standard format for volume assembly — no reel or tape-and-reel variant is listed in this entry.