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USB Superspeed Peripherals

JuIn_1625121
Valued Contributor II

I recognize that it is normal that the input voltage to the RESET# pin is High when FX3 is operating.

However, due to other circuits, the input voltage may fluctuate between 1.5V and 1.9V when FX3 is operating at the customer's board now.

Is there any problems in this case?

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1 Solution
Anonymous
Not applicable

Hi,

Please refer to Table 8 (DC Specifications) in FX3 Datasheet. If your VIO1 is 3.3V, then Vioh ranges fromm 0.625 * VIO1 to VIO1 + 0.3, that is 2V to 3.6V

So the fluctuations in your board might cause problem. We recommend you to rework your board and provide required isolation.

Regards,

- Madhu Sudhan

View solution in original post

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3 Replies
prc_1505996
Contributor

It depends on the VIOH (min) value of RESET pin @ 3.3V (I believe your CVDDQ is at 3.3V). Unfortunately this information is not available in the FX3 datasheet.

Cy tech support, please help.

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Anonymous
Not applicable

Hi,

Please refer to Table 8 (DC Specifications) in FX3 Datasheet. If your VIO1 is 3.3V, then Vioh ranges fromm 0.625 * VIO1 to VIO1 + 0.3, that is 2V to 3.6V

So the fluctuations in your board might cause problem. We recommend you to rework your board and provide required isolation.

Regards,

- Madhu Sudhan

View solution in original post

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prc_1505996
Contributor

Hi Madhu,

  CVDDQ is powering RESET IO, not VIO1. The IO levels for RESET pin may be different from GPIOs. Please clarify.

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