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Thread: 5V Tolerant Devices

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    Default 5V Tolerant Devices

    I created the attached so that I could quickly reference which Altera devices are 5V tolerant. All of these devices have a Vih > 5V. I've also added PDN information as I find that useful.

    Hope this helps someone.
    Attached Files Attached Files

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    Default Re: 5V Tolerant Devices

    This is a good post. However I am not sure if I understand the table completely. Can you explain what the different numbers mean under the package, ex: for EP20K100 you have 2X and 2 under T144 column?

    Thanks.

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    Default Re: 5V Tolerant Devices

    Do you know if there are other devices that are 5v tolerant by using the internal PCI clamping diode with an external series resistor? Or does that only work for 3.3v tolerance?

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    Default Re: 5V Tolerant Devices

    Quote Originally Posted by webjunk11 View Post
    This is a good post. However I am not sure if I understand the table completely. Can you explain what the different numbers mean under the package, ex: for EP20K100 you have 2X and 2 under T144 column?

    Thanks.

    Those are speed grade designations. In the APEX 20K (nonE) family, the -X indicates PLLs are available. -1X is the -1 speed grade with PLLs. -2 is -2 speed grade with no PLLs.

    http://www.altera.com/products/devic...at.html#table1

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    Default Re: 5V Tolerant Devices

    Thanks Novacat. altera has a PDN/PCN subscription you can sign up for, so as these 5V products begin to disappear, you can get notification of last time buy dates automatic.

    https://www.altera.com/literature/up...gistration.jsp

    It also tells you when they issue errata, which I find pretty useful.

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    Default Re: 5V Tolerant Devices

    Quote Originally Posted by Mark W View Post
    Do you know if there are other devices that are 5v tolerant by using the internal PCI clamping diode with an external series resistor? Or does that only work for 3.3v tolerance?
    Mark W does make a good point. Any device that has a PCI clamp diode can receive 5V signals as long as you limit the current by using a series resistor. Most of the Altera Handbooks detail this. You need to make sure that the 5V is not present pre-configuration as the PCI Clamp is off by default.

    You can also do this with an external diode and a series resistor if the device does not have PCI Clamp diodes or you can not ensure that the pin will not be driven pre-configuration.

    My spreadsheet would be quite large if I had to track every device with a PCI Clamp so I have limited it to devices that have a Vih > 5V.

    The devices in the spreadsheet either drive 5V or 3.3V so depending on the destination device you may or may not be able to drive it directly. For example, driving 3.3V will meet the Vih and Vil requirements of a 5V LVTTL device but not a 5V LVCMOS device.

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    Default Re: 5V Tolerant Devices

    Hi,

    I'm interested in using 5 V devices (input and output). I'm new in this FPGA/CPLD stuff, so could someone explain how do I enable PCI Clamp? Some sources say it's enabled by default and some say it's disabled.

    Is there something else what I should consider if I'm supplying 5 V to the board?

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