Input clamp current

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Input clamp current

2,686 Views
publius
Contributor II

Hi,

What's the maximum input voltage level on an un-powered device?

What's the maximum input clamp current of an IO?

I personally find the documentation on the input structure of LPC GPIO pins quite unclear.

Most pins are 5V tolerant, but only with Vdd present. But I can't seem to find the voltage levels when vdd is not present (LPC1317), see snapshot from the datasheet below:

pastedImage_1.png

In another thread it is mentioned that the input structure is a normal input clamp but that can't be the case due to the 5V tolerant pins.

Also, the input clamp current is not specified both for analog and digital pins.

If I follow the datasheet strictly this means that no signal can be connected to the micro-controller that isn't preceded by something that's on the same supply as the controller.

For example, the 3V3 rail of the controller could be short circuited or starting up while a 5V rail remains 5V.

Thanks in advance.

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1,701 Views
publius
Contributor II

Hi again,

Also, what are the specs for the open drain pins,  PIO0_4 & PIO0_5 for the LPC1317?

Are these 5V tolerant and I2C compliant? With or without supply?

Could it be that the datasheet needs updating?

When I look in the datasheet of the LPC111x the open drain pins are mentioned but not for the LPC13xx:

 pastedImage_1.png

pastedImage_2.png

Hopefully someone can help.

Some similar questions:

5V tolerant input 

https://community.nxp.com/message/765563?commentID=765563#comment-765563 

I2C 5V Toterant (with and without supply?)

https://community.nxp.com/message/750299?commentID=750299#comment-750299 

Thanks

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1,701 Views
jeremyzhou
NXP Employee
NXP Employee

Hi,

Thank you for your interest in NXP Semiconductor products and 
the opportunity to serve you.
Unfortunately, the datasheet doesn't contain the kind of information you want and I will report your inquiry for the Doc team.
Thanks for understanding.
Have a great day,

TIC

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1,701 Views
publius
Contributor II

Hi Jeremy,

Thanks for your response. Could you give an indication when to expect the data?

I'm currently designing a product with the LPC1317. 

Thanks.

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1,701 Views
jeremyzhou
NXP Employee
NXP Employee

Hi,

Thanks for your reply.

Sorry, I'm not clear with the exactly schedule of releasing the updated datasheet.

And I will inform if I get it.

Have a great day,

TIC

 

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