The Silicon Labs Si521xx PCI-Express clock generators feature low-power push-pull output buffer technology reducing the external terminating resistors and enabling smaller packaging.

To increase performance they support programmable drive strength, rise/fall times, output impedance and down spread spectrum clock generation is also supported.

The devices support the standard PCIe HCSL signalling format and can be externally terminated to support LVPECL, LVDS or CML levels.

- Push-pull HCSL output buffer technology
- Fully integrated termination resistors on PCIe outputs
- Programmable spread spectrum
- Pin strapping to enable spread spectrum
- I²C/SMBus programmable
- Supports optional LVPECL, LVDS or CML levels
- -40 to 85°C operation
- Individual output enable control
- Small form factor QFN and TDFN packaging