What this CML differential receiver/driver is
The Microchip SY58600UMG-TR is a CML (Current-Mode Logic) differential receiver/driver in a tiny 8-MLF package measuring 2x2 mm. It handles the receive-and-drive side of a CML link, converting differential CML signals to a single-ended or differential output for the downstream logic. The supply rail is 3V to 3.6V, so it sits on a 3.3V rail — not 5V tolerant.
Package and footprint — the 8-MLF with exposed pad
The 8-MLF (2x2 mm) has an exposed pad underneath. That paddle is the main thermal path — without a via array under it, the part derates fast above 70°C ambient. The pad also ties to ground electrically, so the PCB layout needs a solid ground island with at least four thermal vias. The package is MSL 1 per the ROHS3 compliance (no bake needed before reflow if the bag seal is intact).
Supply and signal levels — why the 3.3V rail matters
CML output swing is set by the supply and external termination — typically 400 mV p-p differential into 50-ohm loads. No external termination resistors are required on the output side because CML is self-terminating to VCC, but the input side expects a DC-blocked differential pair. If the upstream driver is AC-coupled, the receiver's input common-mode range sits at VCC – 0.4V, so the coupling caps need to bias the pair correctly.
It is ROHS3 compliant.