Three-port Ethernet switch with fiber support
The KSZ8893MBLI is a 3-port managed Ethernet switch from Microchip that integrates three 10/100 Base-T/TX copper transceivers and one 10/100 Base-FX fiber interface. The management interface is I²C or SPI, selectable at reset, which keeps the host processor pin count low. Supply range is 3.1V to 3.5V, drawing 120 mA typical — about 400 mW on the 3.3V rail. The industrial temperature grade from -40°C to 85°C qualifies it for outdoor telecom cabinets, factory-floor Ethernet drops, and transportation equipment.
Package and supply rail planning
The 100-ball LFBGA has a 0.80 mm ball pitch — a 4-layer PCB with a solid ground plane under the BGA is recommended for signal integrity and thermal spreading. The 3.3V rail must supply 120 mA to the switch core plus any external magnetics and termination resistors. A local LDO or switching regulator with 3.3V output and at least 200 mA capability covers the switch plus margin.
Active production — no obsolescence risk
No end-of-life notification or last-time-buy window has been issued. ROHS3 compliant. For BOM planning, this part is single-sourced from Microchip. The 100-LFBGA package is not a common drop-in for other vendors' 3-port switches, so a layout change would be required for an alternative.