2023-11-20 03:16 PM
Hi everyone,
I'm going to realize a power supply with multiple isolated output for low power audio applications (like preamp, guitar effects...). As voltage regulator I chose the L7809 but in the datasheet there's a note saying "Minimum load current for regulation is 5 mA" (see the attachment).
The problem is that some circuits that I have to supply required less than 5mA.
So, I wonder: what's going on if some loads are less than 5mA? Can I have stability problems? It would be better if I ensure a minimum load of 5mA per output?
Thanks for any support
2023-11-20 03:28 PM - edited 2023-11-20 03:42 PM
right.
so give the dog, what it likes...
on 9V, i would just put 1k at the output to gnd, makes 9mA minimum load current and all is fine.
and dont worry, the world will not die, because you waste 81mW more... 🙂
(but your circuit might die, if the reg begins oscillating... )
or invest 50ct and take a little bit newer version, for low current (<100mA) , like : MC78L09A
at mouser 29ct , 863-MC78L09ABDR2G , 511-L78L09ABZ ...