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According to the LM317 datasheet it says that the adjustment terminal must be bypassed to ground to improve ripple rejection, so that the ripples aren't amplified.

Could anyone explain how this is possible in detail?

I have done quite a lot of research but I don't understand how the adjustment terminal and ripple rejection are linked.

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  • \$\begingroup\$ How about a link to the datasheet you are referencing? \$\endgroup\$
    – jippie
    Nov 30 '14 at 15:16
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    \$\begingroup\$ It doesn't actually say "must". It can be bypassed for a typical improvement of about 7 dB. It probably is related to the "non-idealness" of the current sources within the chip, by reducing the AC impedance of that node to ground, relative to the very large (but still finite) impedance to Vin. \$\endgroup\$
    – Dave Tweed
    Nov 30 '14 at 15:37

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