What this 2:4 LVPECL fanout buffer does
The Texas Instruments CDCLVP2102RGTT is a dual-circuit fanout buffer that distributes one or two clock inputs to up to four LVPECL outputs per channel. It accepts LVCMOS, LVDS, LVPECL, or LVTTL inputs and delivers differential LVPECL outputs at frequencies up to 2 GHz. Two independent 2:4 buffers share the same 16-VQFN package, saving board area compared to using two single-channel devices. The wide supply range of 2.375 V to 3.6 V lets it run from a 2.5 V or 3.3 V rail without an extra regulator.
2 GHz bandwidth — what it means for the timing tree
A 2 GHz maximum frequency covers high-speed serial links like 10 GbE, Fibre Channel, and PCIe Gen3 reference clocks. The differential LVPECL output swing keeps edge rates tight for long PCB traces. If your design runs at 156.25 MHz or 312.5 MHz, this buffer has margin to spare — the jitter contribution at those frequencies is well within the typical 0.2 ps RMS additive jitter budget for most networking ASICs. The 2:4 fanout ratio means one input can feed four downstream PLLs or transceivers without cascading multiple buffers.
Input flexibility and supply rails
The buffer accepts LVCMOS, LVDS, LVPECL, and LVTTL single-ended or differential inputs. That covers the common clock sources on a typical board: an LVDS oscillator, an LVPECL synthesizer, or a CMOS crystal oscillator. The supply voltage tolerance from 2.375 V to 3.6 V means you can drop it into a 2.5 V FPGA bank or a 3.3 V clock tree without a level shifter. Operating temperature from -40°C to 85°C suits outdoor telecom cabinets and industrial controllers.
Package and footprint notes
The 16-VFQFN with exposed pad (3 mm × 3 mm) requires a thermal via array under the pad for adequate heat dissipation when running both buffers at full speed. The exposed pad is electrically connected to the die substrate and should be tied to ground. The small footprint leaves room for decoupling capacitors close to the supply pins — place a 0.1 µF and 1 µF per supply pin within 2 mm for clean power at 2 GHz.
Lifecycle and sourcing
The CDCLVP2102RGTT is listed as Active with ROHS3 compliance. No official second-source alternate is listed, but the CDCLVP1204RGTR is a single-circuit 2:4 LVPECL buffer in the same package — useful as a drop-in for designs that only need one channel.