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Orrin
01-20-2011, 02:08 PM
Gentlefolk:

Can anyone recommend a good source for an SG4501N integrated circuit? It is a dual tracking voltage regulator. I've found an SG4501 on eBay, but it is in a metal package; I need the 16-pin DIP.

This is for a variable power supply that I designed and built in the late 70s. It had constant voltage or constant current modes of operation as well as a crowbar circuit.

The only quote I've had, so far, is $50, each in quantities of five. It's a very versatile power supply, but for that kind of money I can live without it. An outfit here in the States, Four Star Electronics, demands a $400 minimum order.

I've found several overseas sources; but, I'm not inclined to give my credit card number to an unknown outfit.

I came across one mention of substituting a Motorola MC1468, but I'm having just as much trouble finding one of them, too.

Best regards,

Orrin

Orrin Iseminger
Colton, Washington, USA
http://users.moscow.com/oiseming/lc_ant_p/menu.htm

gvasale
01-20-2011, 03:54 PM
Did you try just typing in the PN doing a plain web search? Don't know how much they're worth, or anything else, but the number does come up. Tried Newark Electronics?

alanganes
01-20-2011, 04:52 PM
I may be stating the obvious, but here goes:

If you can get the metal package, you can usually fan the leads out to fit into the appropriate holes in the dip package holes. Have to get creative sometimes, but usually doable.

I'll have to look tomorrow at work, I have the names of a few places that specialize in older parts like this, without resorting to the broker guys that seem to want 50 bucks for pretty much everything.

MaxHeadRoom
01-20-2011, 05:05 PM
Can you sub in a LM125?
http://www.nalanda.nitc.ac.in/industry/appnotes/Natsemi/AN-82.pdf
Depends I guess on how the original was fitted to the board if the pins are not compatible?
Max.

John Stevenson
01-20-2011, 05:07 PM
http://www.oemstrade.com/search/4501N

roundrocktom
01-20-2011, 05:12 PM
Fanning out the can leads is probably the best idea. Especially as he wants only $5 for it.

They [edit, obsolete brokers] stock pile massive amounts of parts, and might charge $50 a part.... but in reality very little of the product ever moves off the shelf.

I still have my LM317 base power supply. Handy project, and has come in handy over the years.

I worked at National Semiconductor in the early 1980's. We had a 10 Amp TO-220 package version, but due to mechanical issues some cases would pop like popcorn. Test floor operator would have to screen by hand, as automatic handlers got jammed by exploding cases. We had a Plexiglas screen to protect the operator, but by the end of a shift poor lady was a nervous wreck.

squirrel
01-20-2011, 05:13 PM
Just plug the TO can into a dip socket and use teflon tubing on the legs. You might have some stray capacitance issues doing that but in an analog regulator it might nothing depending on the circuit and accuracy.

Bruce Griffing
01-20-2011, 05:49 PM
An Octopart search yielded 2 suppliers. I did not look further.

Orrin
01-20-2011, 07:28 PM
Thank you, all, for the helping hand. I appreciate your help. You've given me some good leads.

I'm seriously considering the 4501 in the TO can, but, having fewer leads, its capabilities are not the same as the DIP package. Right now I'm trying to figure out if it would be an adequate substitute.

The LM125 looks promising, thank you. I was not aware of it, before. I had been considering the LM317 because I have some on hand.

Being on dial-up slows my searches to a crawl. Some supplier's sites take ages to download.

Best regards,

Orrin

Bruce Griffing
01-20-2011, 08:58 PM
This site is specifically for people looking for parts. It should not take much bandwidth. Near as I can tell, they list two suppliers for your original part.

http://octopart.com/

Fasttrack
01-20-2011, 09:04 PM
Yes - octopart is a great resource.

I didn't realize the 317 was obsolete, too. I've got a handful of them - used one in my brake controller

Weston Bye
01-20-2011, 09:40 PM
Speaking of obsolete ICs....
I went and checked, and I have 60 unused Z84C5010 microprocessor chips.

These are Z80s with 2K of internal ram - I grouped them with an eprom and 8255 ppi for a 3-chip microcontroller.

Neat concept, but they were late coming to the party and never caught on - Zilog discontinued them.

roundrocktom
01-21-2011, 11:22 AM
Speaking of obsolete ICs....
I went and checked, and I have 60 unused Z84C5010 microprocessor chips.

These are Z80s with 2K of internal ram - I grouped them with an eprom and 8255 ppi for a 3-chip microcontroller.

Neat concept, but they were late coming to the party and never caught on - Zilog discontinued them.

Neat stuff. I also learned, the hard way, not all 8255's in reset didn't act the same (some went tristate, some went low, some went high... ouch!)

Bruce -- cool link on Octopart. Hadn't heard of it before, but I often get the question of "who has stock for.... ".

edit: Fast Track - LM317 are still available. Even the T0-3 version! Yaaaa!

Tom

Evan
01-21-2011, 11:37 AM
A lot of the obsolete parts places online carry no stock at all. They simply copy each others lists and hope to try and find a real supplier that actually has the part in stock if you place an order. The clue to that is they all list the same number in stock.

I checked my inventory and I don't have that part or one like it. I was surprised at that as I have hundreds of types of ICs on hand.

batt-man
01-21-2011, 01:23 PM
Here you go - approximately $20 each (which seems a bit spendy to me)

http://www.mark5.co.uk/search.php?posted=1&stype=any&stext=SG4501N

For what it's worth I've used these guys before and have had good service...

Cheers
Batt

Orrin
01-22-2011, 12:00 AM
Thank you, all. With your help I found a reasonable supplier. I'll be able to afford what I need plus a few spares.

Best regards,

Orrin