Quote:
Originally Posted by Shadowfire
I didn't know that they had started shipping the cyclone 4's yet. Spot check: Digi-key is now showing listings but doesn't have any IC's in stock. Newark is showing a lead time of 30 days.
BTW, Gerbers and schematic will be posted for those who miss the initial order.
I remember checking the Cyclone 4 and I recall reading that the C4's have a maximum I/O tolerance of 3.0V. This is getting close to 2.5V. The quickswitch VCC's could be dropped to 4.0V to support this, but the C4 is going to have less of a noise margin for high level signals.
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The Cyclone III has the same issue. The chip is a lot better at driving 2.5V and 3.0V I/Os than 3.3V I/Os.
The Cyclone III and IV are indeed very similar. For the moment, just the C4 GX is available in small quantities, the C4 E is not available yet.
The C4 E has also a Vcc Int of 1.0V only
Regards,
Frederic