LM7705: Guard band of the 4mV ripple relative to Vout

Hi HSG,

The 4 mV value on page 1 is a typical only, with further details on page 4 and 5 of the D/S.

You can also see figure 5 and 6 which show how the ripple varies.

The LM27761 is a similar device, whose D/S shows lower ripple.

Hi Chris,

Thanks for the quick response and I do understand the 4mV ripple is typical. However what I am trying to understand is when the data sheet shows the maximum or minimum Vout and states then that "All limits are specified by testing or statistical analysis" then I would not expect these Vout values to fall below or above the Vout min or max specifications as the limit should account for the ripple. Is my understanding correct?

Thanks,
HSG

Hi HSG,

It's not entirely clear what you are referring to. Can you give an example?

The output voltage spec, on page 4, is the DC level of the output voltage--what you would read with a meter. The output ripple, with no min/max, is an AC spec. These are independent.

Hi Chris,

Your statement is clear. However a team member was reading a voltage on the output above the maximum voltage as stated in the data sheet. They asked if it was related to ripple causing the higher than expected voltage. I do not believe it is related. I believe it is that the current is higher or lower than the -20mA within there circuit and thus this is why they are seeing a voltage beyond the limit as the limit is specified for when there is a -20mA current.

If you agree with my assessment then I can close this thread.

Best,
HSG