Supply rails and current budget — 3.3V single-rail, 50 mA draw
The LAN91C96I-MU: The controller runs on a single 3.3V supply rail and draws 50 mA typical. That 165 mW dissipation keeps the junction temperature well below the 85°C ambient ceiling even in a sealed enclosure with limited airflow — no heatsink required for most designs.
This qualifies the part for factory-floor automation, outdoor telecom cabinets, and engine-bay-adjacent electronics where the ambient sees -20°C startup and 70°C sustained load.
100-TQFP 14x14 mm — layout and fan-out
The fine pitch demands a 4-layer PCB for reliable fan-out of the 100 signal and power pins — two-layer boards will struggle to route the parallel bus and decoupling capacitors under the body. The exposed pad on the bottom provides a low-inductance ground return; a thermal via array under the pad improves heat spreading.
Parallel host interface — direct bus attachment
The parallel interface connects directly to most MCU/MPU external memory buses without external glue logic. The 10Base-T PHY handles the analog front-end and auto-negotiation, so the host sees a standard MAC-level register set. This reduces BOM count and layout complexity compared to a separate MAC + external PHY solution.
ROHS3 compliance — no exemption risk
For UKCA and EU market shipments, no additional documentation or exemption justification is needed at the BOM level.