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Altera_Forum
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16 years ago

Cyclone III I/O standard

Hi there, in the device family datasheet I read that the Cyclone III device supports LVTTL & LVCMOS. In order to interface the device with standard TTL circuits I think I need some kind of buffer...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

To be on the safe side, indeed use a level-shifter.

But there is an alternative. Check the chapter "5.0-V Device compatibility" in the CII device handbook. This chapter dissapeared in the CIII device handbook (why?), but the theory is still applicable.

But be carefull, only apply the higher voltage after the device is configured, because the clamping diodes are activated during configuration.

Cheers,

Ton

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