CYUSB3025 Crystal Startup / Operation Problems

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
lock attach
Attachments are accessible only for community members.
kebu_4418491
Level 1
Level 1

I am using a CYUSB3025 with an Epson FA-20H 19.2000MF12Y-AG3 crystal. A 100K - 1M ohm resistor across the crystal is needed to get the crystal to startup and oscillate while the SD3 is in reset. Without the resistor, it won't oscillate. When using a startup resistor, bringing the CYUSB3025 out of reset causes the oscillator to stop oscillating. 12pF caps are used for Cext on both sides of the crystal.

The Epson crystal has a load capacitance value of 6pF to infinity. I am not sure what Cext should be. Does anyone have experience using an Epson FA-20H crystal with a CYUSB3025?

According to Cypress lierature, the NDK NX3225SA-19.2M-EXS00A-CS03082 was used to test the FX3. I can't find this oscillator for purchase.

Does anyone have a suggestion for a crystal and Cext values? I have seen examples as low as 2pF and as high as 39pF for Cext.

0 Likes
1 Solution
YatheeshD_36
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hello,

Please refer to the Crystal section in the FX3 Hardware design guidelines: https://www.cypress.com/file/139936/download

The Epson FA-20H crystal is characterized for FX3/FX3S.

You can also calculate the power dissipation of the crystal using the equations 1 and 2 from the FX3 hardware design guidelines.

Make sure that the calculated power dissipation does not cross the max drive level value mentioned in the crystal datasheet.

Thanks,

Yatheesh

View solution in original post

0 Likes
1 Reply
YatheeshD_36
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hello,

Please refer to the Crystal section in the FX3 Hardware design guidelines: https://www.cypress.com/file/139936/download

The Epson FA-20H crystal is characterized for FX3/FX3S.

You can also calculate the power dissipation of the crystal using the equations 1 and 2 from the FX3 hardware design guidelines.

Make sure that the calculated power dissipation does not cross the max drive level value mentioned in the crystal datasheet.

Thanks,

Yatheesh

0 Likes