What does the "H" mean in Part Number UPC78M15H?

high power, 15v/5A

look here:

rw

Thanks for the link, but I looked at the specs there, and it says it is

Still confused....

- Tim -

Because they are confused.

The "M" in the middle indicates lower current output.

The "standard" part would be the 7815, which is about a 1amp 15volt regulator. A 78L15 has about 100mA output and is usuall/always in a to-92 package. The 78M15 is somewhere between the two, I would have guessed 500mA but it's been a long time since I looked it up, and I think is generally in a to-5 package.

I think someone suggested the "H" was for a high current version because there was one device years ago that wasn't a three terminal regulator or something and did use a suffix to denote current.

I don't have a clue what the "H" at the end is for. Suffixes are generally about package type or makeup (such as plastic or metal). The specifics might vary from manufucturer to manufacturer. I suppose the suffix might even indicate temperature range (consumer equipment is generally less fussy in this regard), but I can't say I've ever seen that in regards to three terminal regulators, and a glance at databook shows nothing in this regard.

Michael

This one is in a TO-220 case and has a heatsink on it. It runs very hot, hotter than any other component in the box, even the output trannies run cool compared to this regulator. You can almost burn yourself on the heatsink.

I was hoping that it was indeed a high power unit as that would explain the excessive heat generated from the normal one.

- Tim -

snipped-for-privacy@FreeNet.Carleton.CA (Michael Black) wrote in news:euu28e$o7j$ snipped-for-privacy@theodyn.ncf.ca:

I've seen several devices with an M variant in a TO126 package, kind of like a thin flat TO220. It's a nice package, I wish more devices used it.

accoring to that spec sheet it is a 78M15 in a to220 package. me saying 5A was an error and I removed that ansewr again rw

On Tue, 03 Apr 2007 04:27:00 GMT, Tim put finger to keyboard and composed:

The list of uPC parts in my vrt databook would suggest that a H suffix generally denotes a SIP, SIL, or SILP package. A C suffix appears to be used for DIPs, G for MDIP, and V for SQP. Therefore I suspect that in your case the "H" also refers in some way to the package style. I suppose you could think of a TO-220 package as a "3-SIL" ???

- Franc Zabkar

Tim,

It's an obsolete NEC Electronics part.

Hope it has more info than you have now.

Jeff

I don't think the H means anything of consequence. I don't know why NEC used the M in the middle either. Originally, when Fairchild and Natsemi first started out with these 3 terminal regulators they used

The NEC version is an isolated TO220 plastic type which has a lower current rating (350mA) than the standard metal tabbed 78.. TO220 version available from other manufacturers.

Datasheet archive has a datasheet on the UPC78M00A series here

The A simply denotes a better load regulation than the version without the A and you can substitute this part if preferred.

The original 1A regulators were in TO-3 cases.

Tim,

The "H" probably means high voltage input. The heat produced by a series regulator is the same no matter what the part number.That is if it regulates to the same out put voltage. The series regulators are almost always the hottest semi in a circuit. Ray

Years ago when I ordered those things, the H suffix meant the TO5/TO39 metal can package.

Jeff

Since the linear monolithic regulator first appeared it has grown to encompass many and varied versions and packages. I will disregard all but the original versions in this discussion.

Around 1970-71, before the 78/79 series appeared on the scene Natsemi had the LM340 series +VE regulator series which were available in both TO220 and TO3 cases. And before this Natsemi had the LM309 fixed 5V reg in both TO39 and TO3 cases. Bob Dobkin who worked for Natsemi was credited as the inventor of the monolithic linear voltage regulator.

Subsequent to the LM340 series - around 1972 - Natsemi released the

-VE equivalents to the LM340 series as the LM320 series, however these were only in the TO39 and TO3 cases initially, and sometime later they were available in the TO220 case. Both LM340 and 320 versions were eventually available in TO39, TO220 and TO3 packages (and also smd).

I think I am correct in saying that the 78/79 series series regulators, came after the 340/320 series and were subsequently manufactured by Natsemi, Fairchild, Motorola and many others, and became accepted as the industry standard types. The internal circuitry of the original 78/79 series was almost identical to the original

TO5/TO39 metal

Yep, Natsemi did use the H to denote their TO39 versions - not the M as I said in another post.

That's the way I remember it, that there was the 309 and the 340 series and then sometime later the 78XX numbering arrived. I'm not even sure I remember TO-220 cases in the beginning.

Michael

Well now I'm getting more confused. The part number listed in the service manual, that is on it's way to me, is UPC78M15H. I had the guy that is sending it check for that info. The part was made by NEC, the same manufacturer that makes the 78M15 that is in there now. The PC board is made for a TO-220 style pinout and heat sink, complete with mounting holes.

Am I correct in remembering that a T039 id a round metal can about 1/4 inch across or so, and would have the 3 pads at 120 degree intervals?

- Tim -

I remeber a lot of surplus TO-3 parts hit the surplus market about 6 months to a year after the T)-220 parts hit the streets. They were finally cheap enough for hobby work. You didn't mind buying them by the dozen, instead of asking, DO I REALLY need a regulator for this?

The Online NTE cross reference should list some of the early variations, if they can still supply replacement parts.

Their X ref specs the NTE 968 for the entire *78*15* lineup. Although it does say the output is in excess of 1 amp when heat sinked properly.

I did see someone selling the actual UPC78M15H on the net at about $12 US. A bit steep for a 2 dollar part.

- Tim -