PCIe clock source in a 20-TSSOP footprint
The 557G-05ALFT is a PLL-based clock generator purpose-built for PCI Express (PCIe) reference clocks, delivering up to 200 MHz on four differential outputs from a single crystal or clock input. Packaged in a 20-TSSOP (4.40 mm width), it accepts a 3.135 V to 3.465 V supply and outputs HCSL or LVDS signals — the HCSL format is the standard PCIe reference clock swing, so no external level translation is needed on the differential pairs.
Fanout ratio and signal integrity for the clock tree
A 1:4 input-to-output ratio means a single crystal or clock source fans out to four differential pairs — enough to clock a root complex plus three downstream slots or a switch chip on a typical PCIe lane distribution.
Active lifecycle and compliance documentation
ROHS3 compliant per, so it passes the material declaration requirements for EU and most global markets without a waiver.