What is a Datasheet?

A datasheet (of an electronic component) is an instruction manual on using that component. It explains, its features, what it does, and how to use it.

Datasheets are written by engineers for engineers and can sometimes be hard to understand. In a datasheet, you will most likely want to look for a piece of specific information about that device. You can also use it to choose the correct device for your application.

For example, suppose you want to know which transistor will be best for your power supply design. In that case, you can use the datasheet to know its voltage limits, power handling, current carrying capacity, or the input impedance of an op-amp.

As you would expect, there are thousands, if not millions, of different types of components and their corresponding datasheets. Even the same device made by different manufacturers may have differing datasheets.

How to Read a Datasheet

In general, most datasheets follow a classic format that usually contains an available description, some features, detailed specifications, pinouts and package details, a functional block diagram, and, if you are lucky, some helpful application ideas.

The best way to understand all these is to choose a device and go through its datasheet. You will find datasheets in manufacturers’ books and online. A famous one is https://www.alldatasheet.com/, or you can find in Google “lm555 datasheet,” for example.

You should pay particular attention to the absolute maximum ratings.

You should also be aware that the same device from two different manufacturers can have slight differences. I have found to my disbelief, 555s are with different pinouts!

To explain more, we will choose an LM555 (from National Semi) for our example:

Application Notes

The datasheet above only shows two application examples. The 555, of course, has dozens and dozens of applications and ways in which it can be used.

Shown below is an extract from an LF351 application sheet. Note the design formulas are included. These might not be on the datasheet.

Datasheets are very useful to the designer. I have very seldom come across errors in them. I stock and use devices all the time and it is helpful to print these out and keep them in a flip file next to where I work.