1.8V VDDIO Level in XCORE-200

Technical discussions around xCORE processors (e.g. General Purpose (L/G), xCORE-USB, xCORE-Analog, xCORE-XA).
dcoryh192
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1.8V VDDIO Level in XCORE-200

Postby dcoryh192 » Thu Jan 02, 2020 9:55 pm

Hi,

We are planning on using an XU208-128-QF48 in an upcoming project, and would benefit from being able to use 1.8V I/O levels due to another part with limited support for 3.3V. Is it possible to use 1.8V for VDDIO? There would still be 3V3 for everything else that needs it (USB_VDD33, OTP_VCC).

Thank you
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mon2
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Postby mon2 » Fri Jan 03, 2020 2:06 pm

Hi. I will conclude as no. The datasheet does not list 1v8 as a viable value.

Best to remain at 3v3 and use bidirectional level translators to chat with devices that are strict 1v8 I/O swing. Texas Instruments features a good line of such devices.

As many translators are FET based, the pin drive strength is not very high so do not consider such a component for cable driving. Ok for short pcb trace driving to your target device.

Suggest to post the relevant part of the schematic before moving to a PCB layout when ready.

Hope this helps.
dcoryh192
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Joined: Thu Jan 02, 2020 9:47 pm

Postby dcoryh192 » Fri Jan 03, 2020 8:20 pm

Thank you. Everything is PCB traces, so no drive strength worries though I appreciate the warning. Thankfully the XMOS has a minimal number of connections that I will need. I have other DSPs with the same issue that will cost much more to level shift. If they are able to work at 1V8 then I think I will be OK.

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