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Altera_Forum's avatar
Altera_Forum
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14 years ago

2.5V AS serial configuration device?

I'm finising off a spin of a board and trying to move from VCCIO of 3.3V to 2.5V. We're pin constrained so I'm moving the banks with the configuration pins too. I'm using active serial config a...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

Why using a a 2.5V device at all ? If you still have a 3.3V rail on your board you can power the ECPS16 with 3.3V and directly connect it to the pins on the 2.5 I/O bank. The only thing you have to do is to disable the clamping diode and control your overshoots. This is what application note 447 says. The only problem I see is the small margin for the input high level on the EPCS device (VCC*0.6). Maybe you can reduce the power supply for the EPCS16 device to 3.0V.

Regards,

HJS