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Pin damage by Voltage Source? | Cypress Semiconductor

Pin damage by Voltage Source?

Summary: 1 Reply, Latest post by HIMA on 19 Nov 2015 04:26 AM PST
Verified Answers: 1
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ngohara's picture
36 posts

I have a project that is confusing me at the moment.

We are using a CY8C5667LIT-049  chip,   for a project using USB to set currents with IDACS and read voltages with ADCS.

We have two power supplies for this board, a 3.3V and 5V source, both have diodes between source and "VCC" for the chip.
The 5V source is the USB input to our board.
In order to detect a USB connect, I have a GPIO connected to the USB 5V directly, as an hotplug-detect interupt (labeled VBus in my project).

On our current board, this Vbus pin would receive around 5V, while the VCC would be 4.7V from the diode drop.
According to family data sheet (CY8C56lp family)  the GPIO pins should have  VDD+0.5V  range, so this should be safe.
However, this pin currently does not read high, even when I multimeter measure 5V on it.
Could this pin still be damaged by the 5V source, even though its within the specs? A surge from the source or something?

If you could recommend any modifications to properly detect the 5V usb being plugged in, I would appreciate it.

Thank you


HIMA's picture
Cypress Employee
169 posts


Please let us know if you have connected the VBUS pin directly to the PSOC GPIO. Can you please check the VBUS monitoring section the USBFS Component datasheet.If you have enabled external VBUS monitoring then there is a recommended circuit for connecting VBUS to GPIO.



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