Best Way to Find Equivalent of Deprecated Parts Family - Page 1
Forum section: electronics / beginners

author: The13thParish
author_rank: Contributor
timestamp: February 08, 2021, 12:43:35 am
content: Dear all,I'm looking to build a circuit which sets/resets the domains in a Honeywell Aerospace HMC2003 magnetometer for greater sensitivity readings (schematic attached). The parts list includes a few transistors which don't seem to be manufactured anymore and in terms of datasheets I don't really know what the important properties I'm looking for to find a more modern equivalent.General guidance is much appreciated. If anyone is inclined to offer more specific advice, the transistors in question are:2N2222- it seems these are all sold in bulk, which I do not wantIRF7105N- these seem to be a deprecated family of transistorsIRF7105P- these seem to be a deprecated family of transistors[\list]All the best,Ryan

author: bob91343
author_rank: Super Contributor
timestamp: February 08, 2021, 02:17:13 am
content: The 2N2222 is one of the most common transistors. It's also available as PN2222 and other prefixes, all the same die. There is also the 2N2222A. You can find these at any distributor. Check All Electronics as an example. They should cost a few pennies.As for the FETs they seem simple enough to replace with modern parts. They are 25V rating and probably nearly any type will work.I assume you have this document:https://aerospace.honeywell.com/content/dam/aero/en-us/documents/learn/products/sensors/application-notes/AN213_Set_Reset_Function_of_Magnetic_Sensors.pdf

author: mvs
author_rank: Frequent Contributor
timestamp: February 08, 2021, 02:25:28 am
content: 2N2222 and 2N2907 are complementary BJT pair and are usually to cheap (0.01-0.02$/pcs) to be sold individually. You can replace them with other pair, like BC817 and BC807.IRF7105 is a dual MOSFET (N chanel + P chanel) in SO8 package and is currently still in production. You can replace it with DMC3025 or AO4606.

author: The13thParish
author_rank: Contributor
timestamp: February 08, 2021, 02:44:22 am
content: Thanks folks, all very helpful.

author: Whales
author_rank: Super Contributor
timestamp: February 08, 2021, 04:21:31 am
content: A quick note on part sourcing: traditional retailers vs greymarket.Traditional retailers include companies like Digikey, Farnell/Element14, RS components, Arrow, LCSC and others. They cost more but they (mostly) control their supply chains & provide datasheets for their parts. Sometimes they screw up, but they almost always correct problems when told about them.Greymarket sellers use sites like Aliexpress, eBay and the likes. These sellers most often don't know much about what they are selling other than what's written on the chip. For cheap parts like "100pcs 2N2222 transistor" they are a great source, but for some other parts there are higher risks of bad quality or fakes. It's often worth buying from a couple of different suppliers. If they screw up they often just provide a refund and nothing more.

author: wizard69
author_rank: Super Contributor
timestamp: February 09, 2021, 12:52:24 am
content: As others have suggested the 2N2222 is possibly one of the most popular transistors out there. Buying them in quantity should not be a problem as they are very useful and cost pennies apiece (well 60¢ at DigiKey for 10) even from a proper supplier.As for the other FETs it never hurts to look up what the manufacture may have online for a cross reference or replacement list. Sometimes they have a technical support area where you can submit a question.

author: Jwillis
author_rank: Super Contributor
timestamp: February 09, 2021, 03:53:30 am
content: The IRF7105N and the IRF7105P are on the same chip .https://pdf1.alldatasheet.com/datasheet-pdf/view/392394/IRF/IRF7105.html

author: tooki
author_rank: Super Contributor
timestamp: February 09, 2021, 06:46:35 pm
content: Since this topic (supposedly obsolete transistors which actually aren’t) has come up multiple times recently, I think it’s important to emphasize the need to learn how to “read” part numbers, in the sense of figuring out what the “base” part number is, and which parts of the number refer to variants, like case and packaging options. For example, a PN2222 is just a 2N2222 in a plastic case instead of metal can.In other words, you shouldn’t give up if you only find a part that’s got a slightly different number: look at the datasheet and see if it’s actually the same. For example, an NE555, SE555, and LM555 are just different manufacturers’ designator for the 555 timer, and are entirely interchangeable.