Industry Standard Multisourced Parts: Why Everybody Makes 1N4007

If you run a search on the DigiKey website for 1N4007, you find almost a hundred results in our Single Diodes section, both through-hole and SMD, from eighteen different manufacturers. Which of them is the “real” 1N4007, then?

The answer is that they all are.

1N4007, and many other parts that follow a similar “1N…” part numbering format", is an example of an industry standard multisource part - an old, common device from the early days of electronics that has proliferated across the globe. No single company controls these products. Instead, each different standard part has a set of specifications it conforms to that define what that device is, and many different suppliers all offer their own versions of a part that meets this common specification.

Despite this common specification, astute customers will note that there’s a myriad of parametric variations amongst our offerings for 1N4007. Differences in forward and reverse voltage, differences in leakage current, differences in capacitance. If all these products are the same product, how can these differences be tolerated?

The answer lies in the age of these products. Parts like 1N4007 are old. These devices were developed decades ago, when manufacturing and engineering capabilities were not up to modern spec. The common specifications for these products have tolerances far looser than modern engineers would generally accept in a new product, and some suppliers attempt to differentiate their versions of common parts like these with strictly-better ‘improved’ specifications. Some variation can also arise from differences in manufacturer testing methodology - test a part two different ways, and you will arrive at two similar but not identical results.

The pertinent fact to keep in mind is that if your design calls for a 1N4007 or other similar “1N…” standardized part? You can use any of the parts under that name so long as you get the right package. A design that wants the base specs for 1N4007 won’t care about the improved performance of some of these diodes, any part that meets the standard will work. An engineer who designs in one of the ‘improved’ 1N4007 with higher specs will need to call out that specific variation of the part, at which point they’re not really using a 1N4007 anymore.

These parts can be thought of as the standard Lego bricks of the electronics industry. They’re old, a little boring, and they’re not as slick or sleek as newer, fancier specialized parts are, but everybody knows how to use them and they’re commonly available everywhere you look. A two-by-four blue Lego brick is functionally the same as a two-by-four red Lego brick, just like a Diotec 1N4007 is the same as an onsemi 1N4007. You can build a cool spaceship with either brick or either diode.


image courtesy of Wikipedia

One thing they all have in common is that they meet the minimal JEDEC specifications for 1N4007 silicon rectifier diodes.

All parts with 1N (diodes) or 2N (transistors) prefixes are JEDEC registered components. So by designing a circuit to only require the JEDEC specs, and not rely on the extra parameters, you can be assured the parts are fully interchangeable.

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I’d say this is a very important point. There may be circuit designers that prefer doing Bob Pease -style engineering - design by testing: Making a circuit work by using state-of-the-art “SiC based 1N4007s”, and then in the production assembly is done using left-over stock parts from the seventies… what could go wrong? If a 1N4007 performs too well, it should not be named as that. Instead of having device specific specs for minimum or maximum, the specs should define both.
Cheers, heke

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