The CY2Dx15xx family of devices was designed to accept differential input reference clocks-- LVPECL, LVDS, or CML type inputs, depending on the device. Device datasheet specifications depend on the use of a differential input meeting requirements defined in the datasheet. The CY2CP1504 was designed to accept single-ended LVCMOS inputs and is recommended in applications requiring fanout of an LVCMOS clock signal to LVPECL outputs.
In order to use one of the CY2Dx15xx devices with a single-ended reference input, a special termination network may be required, and some datasheet specs may not be guaranteed under all conditions. In such cases, please consult the factory to receive support from a Cypress product line applications engineer.