Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

StratixIVGX core voltage supply issue from devkit

Hi dears:

I'm study Altera's IVGX SI devkit schematic, and prepare to design my board. But i was confused by the core voltage of the schematic as attachements shown.

The 4601 can't convert 14V to 0.9 according the ltm4601 datasheet, and how Altera guys to get the 0.9V from LTM4601?

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    Yes, according to the LTM4601 datasheet 14 V or even 20V to 0.9V are not guaranteed by design. I guess, the Altera design is relying on the typical ton(min) rather than the maximum value, as good design practice would require. So you should go for a different switcher device.

    Similar problems exist with most synchronous switchers. Usually, they require to reduce the switching frequency for large voltage ratios, but this option doesn't exist with LTM4601.