My design integrates a Cypress FX3 CYUSB3014-BZXC and I need a GPIF 100MHz 2.5V interface.
There is no problem to set VIO1, VIO2, VIO3, VIO4 and VIO5 to a 2.5V voltage supply.
But, for saving a LDO, I also would like to supply CVDDQ with 2.5V.
And in the datasheet, it is not easy to know if it is possible.
In the section 'Operating Conditions' on page 19 we can read:
VIO1, VIO2, VIO3, VIO4, CVDDQ
Supply voltage ......................................................1.7 V to 3.6 V
But in the section 'Power' on page 11 we can read:
CVDDQ: This is the supply voltage for clock and reset I/O. It
should be either 1.8 V or 3.3 V based on the voltage level of
the CLKIN signal.
In my design, CLKIN and CLKIN_32 are floating because I am using a Crystal 19.2MHz EXS00A-CS05400 connected to XTALIN and XTALOUT.
So as I do not use CLKIN inputs, can I use a 2.5V voltage supply for CVDDQ ?
Thanks in advance,
If you are using a crystal, it is ok to use 2.5 V for CVDDQ.