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Altera_Forum
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14 years ago

Using LM317 to power FPGA

Analysing a couple of schematics I found out some using this device. Declared input voltage is 5..9v. Research of datasheet for LM317 shows that Vin-Vout should be >3v. Thus it will not be possible t...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

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There's a dropout voltage diagram in the datasheet. It clarifies that 1.7 V differential is too low if the input voltage is as low as 5V. 6V input voltage (actual minimumm, considering voltage ripple!) would be O.K. You should use a typical LDO regulator.

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Thank you for reply. Will LM1117-3.3 help? It seems to have 1.5v dropout. However it has 800ma...1A current rating...