TI's datasheet says 220nF on the input pin (though I also use 100nF), but nothing on the output pin. I prefer a 10uF aluminium electrolytic on the output, as it acts like a zobel network due to its large ESR. I think it was something recommended by Bob Pease.Definitely there must also be a bypass capacitor at the input to that regulator. I had a similar experience and it was oscillating at several megahertz. The fix was adding the input bypass close to the regulator. Just like the app note states. 0.1 mfd within 1/2 inch. consult the application notes for their suggestion of how close.
Hi Martin, do you have a source for that? I made a lab supply with LM7808, LM7908, LM317 and LM337. The LM7908 starts to regulate correctly around ~3mA. I cannot find this requirement in the datasheet or online.These regulators need a load of at least 5mA to stabilise properly. Try loading it with 1K and measure the voltage.
Wow, I totally missed that.LM7805 lists the minimum current here:
How is that different? I mean, it would be the minimum load current required for the device to operate properly wouldn't it?NO, that is not a minimum load current, that is the load current range for which the device is guaranteed to meet the voltage output specification. Spec sheets can indeed be confusing sometimes.
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