Telecom transceiver in a 144-FCBGA
The VSC8486YJB-11 is a single-circuit serial transceiver from Microchip, built for telecom line-card applications. It dissipates 750 mW and comes in a 144-FCBGA package measuring 13x13 mm. That power figure sets the thermal budget for the board — the FCBGA's exposed pad and via pattern under the die need to pull heat into an inner ground plane to keep junction temperature in check.
Package and footprint constraints
The 144-FCBGA (13x13) is a fine-pitch BGA — expect a 0.8 mm or 1.0 mm ball pitch. The board needs at least four layers to fan out the inner rows; a two-layer board will struggle to route the centre balls without blind vias.
No direct pin-to-pin second source is listed; the serial transceiver function is specific enough that a drop-in alternate would need to match the FCBGA footprint and the serial protocol.