4 Replies Latest reply on Apr 28, 2020 10:16 PM by SananyaM_56

    CYUSB3304-68LTXC USB 3.0 Hub only recognized with a chance of 50%




      We have a design with an ultrascale+ MPSoC and a CYUSB3304-68LTXC.


      After power up, the USB 3.0 Hub is only recognized with a chance of around 50%. After it's recognized after power up, everything works fine. Data transfer rates are really great (super speed) and everything works stable.


      If the CYUSB3304-68LTXC USB 3.0 Hub is not recognized after power up, we can still use the USB 2.0 Hub part without any problems. If we set the CYUSB3304-68LTXC reset pin to low and high again, the USB 3.0 hub will also work fine. But that is no real solution for us because it have to work directly from first power up.


      It's a strange behavior. The CYUSB3304-68LTXC should work together with the Ultrascale+ MPSoC.


      • The board is a 12 layer design with calculated impedances. A lot of other high speed stuff like DDR4 works well on it.  
      • The crystal is a TSX-3225 26.0000MF09Z-AC0 designed for 9pF load capacity. We have 2x10pF connected, together with spray capacitance and the input pins we expect that this should fit.
      • The reference resistors (6,04k + 200) have 1% tolerance as requested.
      • We are using the integrated ROM (Both Mode_Sel connected via 10k to 3.3V
      • I2C Pins are connected to our processor, but not used (4.7k pull-ups)
      • The US-tranceiver pins have 0.1uF capacitances (AC-coupled). (Sure, DS TX have them also)
      • We have tried already a delayed release from reset, but no changes.


      Have somebody an idea or hint for me?


      Best Regards,