The CY25403, CY25483 and CY25423 have three programmable
PLLs that can be used to generate output frequencies
ranging from 3 to 166 MHz. The advantage of having three PLLs
is that a single device generates up to three independent
frequencies from a single crystal.
Input Reference Clocks
The input reference clock can be either a crystal or a clock signal,
for CY25403 and CY25423 while just a clock signal for CY25483.
The input frequency range for crystal (XIN) is 8 MHz to 48 MHz
and that for external reference clock (EXCLKIN) is 8 MHz to 166
MHz. The voltage range of the reference clock input for CY25483
is 2.5V/3.0V/3.3V while that for CY25403 and CY25423 is 1.8V.
This gives user an option for this device to be compatible for
different input clock voltage levels in the system.
VDD Power Supply Options
These devices have programmable power supply options. The
CY25403/CY25483 is a high voltage part that can be
programmed to operate at any voltage 2.5V, 3.0V, or 3.3V while
CY25423 is a low voltage part that can operate at 1.8V.
Output Source Selection
These devices have programmable input sources for each of its
clock outputs. There are four available clock sources and these
clock sources are: XIN/EXCLKIN, PLL1, PLL2, and PLL3.
Output clock source selection is done by using four out of four
crossbar switch. Thus, any one of these four available clock
sources can be arbitrarily selected for the clock outputs. This
gives user a flexibility to have up to three independent clock
outputs.