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For example, the below snap shows different manufacturers for the same series name. I see the description wildly different for the 3 transistors under D45C2.

http://www.datasheetcatalog.com/catalog/p393920.shtml

Why are they mapped under same series name? As far as I know ICs like the 555 timer or 741op-amp can have a generic series name independent of manufacturer.

Of course there will be further differentiating numbering for supplier websites, but the below naming similarity is confusing for a PNP transistor.

enter image description here

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    \$\begingroup\$ That may help. electronics.stackexchange.com/questions/462752/… \$\endgroup\$
    – OJazz
    Feb 28, 2022 at 11:57
  • \$\begingroup\$ They can, and whether that's a good idea is a wholly different Question. Which matters for you? The freedom to choose, or the likeliness of meeting the buyer's needs? \$\endgroup\$ Feb 28, 2022 at 20:23

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Manufacturers, in general, can use whatever name they want, even if the characteristics or even functions vary.

If they are members of some organization such as JEDEC they may have agreed upon some commonality in specs for a certain range of possible part numbers.

So to get a unique ID you need both the manufacturer name and the full part number, ideally. In practice they may have changed the part over time and you may need date codes or internal or external revision codes in addition. Sometimes similar but not identical parts are made in different facilities with slight differences such as materials or bonding wire type and sold with numbering that is very similar or identical. Usually it doesn’t matter, but sometimes it does.

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Yes, it's quite common for manufacturers to use the same part number. Sometimes it may be (or have been) an official second source. Sometimes it means they built a clone of another manufacturers part. Sometimes it might be a complete coincidence and the parts may be totally unrelated.

Often a part with the same part number from a different manufacturer will be an acceptable substitute, but you should probably verify it before committing to production with the new part.

Don't read too much into the descriptions posted on aggregator sites, often they just copy the title of the datasheet, and the datasheet often covers multiple parts. You really need to actually read the datasheet to figure out the details of the specific parts. It's quite possible for two equivalent parts to be described completely differently if different manufacturers have chosen to highlight different aspects of the parts or chosen to group different selections of parts into the same datasheet.

The word "Complementary" doesn't refer to the characteristics of any individual transistor, but refers to the fact that the manufacturer offers both a NPN and a PNP (or N channel and P channel for FETs) transistors that are designed to complement each other.

Similarly the 30V-80V seems to refer not to the voltage rating of any individual transistor (transistors don't generally have a minimum voltage rating as such), but to the range of different voltages covered by that datasheet.

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Don't use that website (data sheet catalogue) for making comparisons; find a proper supplier (Farnell, RS components, Mouser, Newark, Arrow or Digikey to name a few) who sell several devices with the same generic name and, inspect the data sheets to see how similar they are.

Of course, if the "similar" parts are from leading silicon suppliers then they can be pretty much trusted to deliver near-enough equivalent parts but, as in all cases, you should compare the data sheets against your own circuit requirements.

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Simple answer: Yup

More complicated answer:

Consider the humble 4-inch #2 Philips screwdriver. If you search, you'll find a bazillion manufacturers of 4-inch #2 Philips screwdrivers.

  • Some of their products are 4 inches long. Some a little more. Some a little less. Some are actually measured in metric units and deemed close enough to be called a 4-inch screwdriver.
  • The diameter of the shaft is a bit more for some, a bit less for others.
  • Some have rubberized handles, some not.
  • Some handles are yellow, others red, others blue, others a bit closer to tie-dye.
  • The point on some is rounded, others sharp.
  • The metal on some is very hard. On others it's so soft you can pick a chip out of it with your finger nail.
  • I won't even go into the many different descriptions/names for said screwdriver.

The question isn't "is it really a 4-inch #2 Philips screwdriver?" because they most certainly are. The question is, which of the bazillion 4-inch #2 Philips screwdrivers out there is the right one for the job you're doing?

And that's the problem you're facing. If you need a D45C2 transistor, then every one of those are a legitimate option. But, as usual in most aspects of life, which one is right for your application requires you to do a little research.

I love manufacturers. But I only trust them to a point.

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    \$\begingroup\$ We also have Philips vs JIS (Japanese standard with a 'dot' usually on the head of the screw). They're close enough that a Philips screwdriver sort-of works in a JIS screw but tends to cam-out and ruin the screw head. There's also similar-looking 'star' Posidrive and Reed & Prince Frearson but we don't usually see them in electronics, at least IME. \$\endgroup\$ Mar 2, 2022 at 11:07

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