CY7C65632 HUB is not working

[uuygun]

Hello there,

We designed a HUB using the CY7C65632. We use it as self-powered. Our problem is that the HUB is not detected by the host. To clarify the problem, some of our observations are:

We use the power-on reset circuit recommended in the datasheet, but the reset voltage that should rise to 4.2V seems to be 2.2V here. When we pull it to 3.3V and save it from reset, the HUB is recognized. But the devices we connect to the hub are not recognized. We are getting an enumeration failed error.

We cannot see 3.3V at the internal regulator output, we get 3.9V-4.2V. If the HUB is detected, the regulator voltage is 3.9V. If the HUB is not detected, regulator output is 4.2V. In both cases we don't get 3.3V. What could be the reason for this?

We see 12 Mhz oscillation in our crystal output, but a DC offset seems to be superimposed on this wave and thus the level of the oscillation exceeds 3.8V. Could this be due to the crystal capacitors not being placed close enough to the corresponding pins? Or why else might we be seeing this offset?

Many thanks in advance for your help.

[MallikaK_22]

Hi,

Please provide your schematics for review, if not confidential.

Regards,

Mallika

[uuygun]

Can you share your e-mail address? I can send it there.

[MallikaK_22]

Kindly send it to mallika.khare@infineon.com

[uuygun · Accepted solution]

Thank you so much. No help needed for now. We identified the source of the problem.

The IC has no GND pins on any of its legs, only its exposed pad. And we skipped making the ground connection to the exposed pad, that's why the problem was. When we connect the ground, the problem was fixed.