Regulator Datasheet Parameters meaning!

[Shahriar]

Hi
The datasheet I have attached belongs to LM317.
I Want to know how much ripple do we  have for a Specific Output Voltage and current.  ???
I would appreciate it If you could help me through an article to understand the Parameters Meaning.
i.e. Ripple Rejection Ratio, Long-Term Stability, ...


ThanX a million
Shahriar

LM317B.pdf

 

[audioguru2]

Hi Shahriar,
The LM317 has a voltage reference and changes to it are amplified by how much higher than its reference voltage is its output voltage. Therefore the conditions for the ripple spec's are with an output voltage of 10V. The output ripple will be lower with a lower output voltage and higher with a higher output voltage.

Without a cap on its adj terminal, its typical ripple rejection is 65dB, which is 1/1800th of its input. So an input ripple voltage of 1V will be reduced to 0.56mV at its output.
The ripple rejection is 80dB typical with a cap so 1V at the input results in 0.1mV at its output.

The long term stability is a typical voltage change of 0.3% when it is operating extremely hot, after 1000 hours. They guarantee that its voltage won't change more than 1%.
It probably has much better stability (its voltage will change less) for much longer if it was operated cooler.

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