Datasheet Lists TYP Values only - how to estimate worst case

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matthej

Joined Oct 10, 2020
38
Hi,

I come across a datasheet that lists typical current consumption values and then mentions to provide significant margin when designing your power supply design.

My question is:

Is there a number to assume or is it part to part dependent?

Thanks!

Datasheet is attached. page 61 is where these values are listed
 

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Papabravo

Joined Feb 24, 2006
16,188
Current consumption is not one of those things that can be controlled by a semiconductor device. It depends in large part on what you ask the complex semiconductor to do. You would not want to design a product and try to make it run reliably by using a power supply that was limited to anything close to those typical numbers. If you are really concerned about it you can take some data yourself before you commit to a final specification for the power supply.

For the rest of the datasheet you can infer that a typical value is the mean of a normally distributed random variable. If they give either a min or a max along with the mean you can start with a hypothesis that it represents a 3σ value away from the mean. That hypothesis says that 99% of all the parts you encounter will be in the range of the mean ±3σ above or below the mean. If you want to track this you can measure a selection of individual device to confirm or reject that hypothesis.
 

Papabravo

Joined Feb 24, 2006
16,188
The answer is always...
42
Like the answer above, you can assume anything you want. Does your assumption have any basis in reality is another question. In particular you have no ability to complain if a device falls outside of your assumed parameters. Like I said, you can measure it, if it is that important, or you can ask the manufacturer if they have any additional information on the subject. Use the product or don't use it. They may or may not care which way you decide.
 
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