Device function and protocol stack
The LAN9730-ABZJ-TR is a single-chip bridge that converts a USB 2.0 interface to a 10/100 Base-T/TX Ethernet PHY, integrating the MAC and PHY in one 56-QFN package. It implements the full USB 2.0 specification on the host side and the IEEE 802.3 10BASE-T and 100BASE-TX standards on the network side, auto-negotiating speed and duplex. The 3.3V single-rail supply simplifies power tree design — no additional 1.8V or 2.5V rails are required for the core.
Package, footprint, and board integration
Housed in a 56-VFQFN with exposed pad (8x8 mm body), the LAN9730-ABZJ-TR requires a thermal land pattern on the PCB to dissipate heat from the integrated PHY. The 0.5 mm pitch QFN demands a solder paste stencil with 0.25 mm aperture openings and a 0.125 mm step for the centre pad to avoid bridging. The package is moisture-sensitive — store unopened reels in a dry cabinet or bake before reflow if the floor life has been exceeded.
Active lifecycle and compliance status
It is ROHS3 compliant, meaning no restricted substances above the threshold limits — no additional exemption declarations are needed for EU market placement. The TR variant ships in standard 13-inch reels with 2500 units per reel, suitable for automated pick-and-place. The CT option is available for prototype or low-volume builds without committing to a full reel.