PLL with bypass and 1:8 LVPECL fanout
The 8T49N281C-999NLGI is a FemtoClock® NG PLL clock generator from Renesas that accepts a crystal input and delivers eight LVPECL outputs. The PLL includes a bypass mode, allowing the input reference to pass through uncorrupted when the PLL is not needed — useful for system test or failover scenarios where the clock source must remain deterministic. The 1:8 fanout ratio distributes one clean reference to eight loads without external clock buffers, saving board space and reducing additive jitter from additional fanout devices. The differential LVPECL output is specified for high-speed ADC/DAC reference clocks and serial data links where edge symmetry and low phase noise are critical.
The 56-VFQFPN package with exposed pad (8x8 mm) requires the thermal pad to be soldered to a PCB ground plane for rated thermal performance. The single-circuit PLL with a 1:8 ratio means one reference input drives eight outputs — the divider/multiplier is Yes/No, so frequency synthesis is handled by the PLL feedback divider, not an output multiplier.
Renesas lists the 8T49N281C-999NLGI as Active with no NRND or EOL notice. The part is ROHS3 compliant, covering the full RoHS exemption list without time-limited carve-outs — relevant for EU and UKCA markets where ROHS2 exemptions are expiring.