# Why do manufacturers specify typical values, not just maximum and minimum?

Why do manufacturers specify typical values? I am still going to have to design my circuit so that it can accept values within the maximum/minimum values.

What is the probability of getting a "typical" value component? Is it standardized?

For example, the datasheet for a TL081, on page 12 there is a table of electrical characteristics. Which tells me the input offset voltage is typically +-1mV. But if I need 1mV then I'll have to go find a different op-amp because its not within the max of +-4mV.

• Thank you for pointing out there is a graph :). I am more interested on if there is an industry standard or not or if I have to find the graph every time. I don't actually have an application which cares that much about the "Input offset voltage" it was just the first line with "typical values" in the first datasheet I thought of as an example. Apr 28, 2021 at 7:53
• I guess you could use a "typical" value to center some operating point. Probably not in this case, though. Apr 28, 2021 at 8:05
• Apr 28, 2021 at 8:14

It is not standardized how often typical values actually are seen in your parts. But many datasheets also show histograms of the distribution. For example with your TL081 it is in Figure 6-1:

This histogram can help you to decide wether it is worth choosing this cheaper part compared to a more expensive one (you just might have to do production testing and sort out the few chips that fall outside your tolerance range).

But be aware that these histograms often are no guarantee either. The maufacturer may have a footnote explaining that the distribution comes from just one manufacturing batch and the distribution may vary at other days.

There are several reasons why a manufacturer might want to specify a typical value additional to the min/max values: It might be just a marketing "trick" to be able to show some nicer values.

But in other cases it is just that guaranteeing e.g. a max input bias current in the fA range is extremely expansive in terms of testing. If the manufacturer gives a max value of 10fA he basically has to test each an every part to comply with that spec. This intensive testing increased the price of the part. If the manufacturer just does some basic testing the part can be sold to a lower price. Then the max rating can say something like 1µA, while in reality 99% of parts fall within the typical range of 10fA.

Offset voltage is also based on many other parameters. check page 17 and below to see the graphs!

Based on my experience, you may search for another datasheet (there can be many datasheets for the same product) for the part you are interested to, it might have more information. There are many cases where datasheets wont show you what you want (max/min values or even some useful graphs).

In that case, you may as well pick another part entirely.