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trying t build a replacement part for obsolete IC ?

hello, I am trying to find a compatible replacement for an obsolete hard to find part SN75518N

Afer much searching and reading and learning i thought maybe i could build a compatible circuit to perform same function as SN75518 ? I think i can cascade 2 of the MAX6971 to cover what is used on the 75518.

could someone look at these and see if i am on track or lost ?

if lost... can someone give me a landmark ?

use 2 of these

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to build this (-2 od the outputs)

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to drive a 16 alpha-numeric char VFD (16 segment)

thanks for your time and help, rob

Reply to
robb
Loading thread data ...

Try this instead:

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-- Joe

Reply to
J.A. Legris

See if the Allegro still makes the UCN-5818. (With various suffixes). Sprague Semi.(now Allegro) said that it was a replacment for the SN75518.

Mark Zenier snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)

Reply to
Mark Zenier

You're getting side-tracked. Replace the part using the previously recommended vendor and put the machine back together, before you get run over by a pie wagon.

Purchase a spare, if you suspect peripheral involvment in the original failure.

RL

Reply to
legg

Thanks for perspective,

I thought i might be but the parts are so difficult to get... if you are not ordering $ 300 - 500 of stuff then the chip brokers of obsolete parts (and there are lots of the chips out there) do not want to talk to you.

so i try to find solutions i can get as end udser like Mouser/Digikey/Arrow etc

thanks again for advice, robb

Reply to
robb

find

thanks Mark,

perfect suggestion if that chip were not as difficult to buy as the SN75518N. All those chips exist out there when i do search for them the SN75518N,UCN5818N,UCN6818 etc i just can not purchase them as they are stocked by huge chip warehouses and they only deal through brokers and the brokers only deal with minimum orders of $300-500

so i try to find solutions i can buy thanks again for your help, robb

Reply to
robb

find

build a

Thank Joe,

i have same reply as for others... Perfect suggestion if that chip was not as difficult to get as the SN75518N all those chips are availbale through brokers if you are spending $300+ dollars otherwise they do not want to help. but still a perfect suggestion

so that is reason i was trying to find an alternate solution with parts i can actually buy.

thanks again for help, robb

Reply to
robb 

--
You can actually buy an Allegro A6818SEP-T from Digi-Key for 5.06
USD and if you want more than one, they have 3031 in stock:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=620-1094-ND

It appears Arrow also has them:

http://app.arrownac.com/aws/pg_webc?s=P
Reply to
John Fields

...

...

Random suggestions: Jameco, JDR Microdevices, B&D Enterprises, (The mail/web order specialty distributors that are small order friendly and stock some surplus/chip pulls/older inventory). There's also places like Rochester Electronics who specialize in the discontinued parts but often deal with only mil-spec stuff ($$$$).

Your Milage may vary, I have not spent the time to see if they have any.

Also check out the thread "Obselete Devices" in Sci.electronics.design. one of the regulars has set up some sort of custom Google search that weeds out those parts brokers with imaginary inventory.

Mark Zenier snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)

Reply to
Mark Zenier

SN75518N

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?name=620-1094-ND

Well John, how embarassing :}?

but, i 'd rather be embarassed with chip than honored and chipless. as it turns out i was looking for ucn6818 like the ucn5818 so a partial

6818sep helped

so do you have a idea for simple conversion of the PLCC pkg to DIP-40 an adapter perhaps ???

thanks for chimeing in, robb

Reply to
robb 

--
Probably, but they're usually hideously expensive.

Was the 75518 soldered in or socketed?
Reply to
John Fields

to

D

soldered robb

Reply to
robb

Hi Rob, why give up SN75518N? what is the quantity you need for your project? if it is below 30k, you can continune to use it. we can support you at this item.

best regards, Peter snipped-for-privacy@expertonic.com

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Reply to
Peter

Shenzhen, China?!?! I think Rob wants *REAL* SN75518N's......

Reply to
GPE

FWIW, I have heard for people emulating obsolete chips with microcontrollrs or PALs. I wouldn't be surprised if that's what you would get if you ordered a significant number of them from an Asian supplier.

Al

Reply to
Al

you know after doing all this searching for the chip i was going to ask a question along those lines but then i thought i would get some feedback like

yea you can with $900 chip burner and $250 programming software, couple of months microcode/controler development experience and a couple of weeks of testing and you better buy a tube of chips in case you fry a couple and then you need a testing board and setup ........

so i did not ask :) robb

Reply to
robb

You're correct. But as a retired engineer and an electronics hobbyist, I have all that stuff. So far my cache of obsolete parts has kept me supplied with all the goodies I need so I hadn't needed to do that. People have been known to put together reasonable chip burners for almost nothing and use free software to generate their code. I've been fortunate in that I have the time and patience to do it.

It's much cheaper to buy all the gadgets I make for myself, but there is the pleasure of the hunt ;-)

Al

Reply to
Al

"robb" wrote in news:13f09a1cpvt8921 @corp.supernews.com:

To build?

If there is room; An adequate sized perf board with two rows od common .1" headers, perhaps with mating sockets on the one board. Also on the perf board woth be a PLCC socket with through hole .1" pins, the socket point-to-point wired to the headers. A little less witing, and you can use a surface mount socket, or solder the chip down, if you fab a PCB.

Reply to
Gary Tait

I'd try

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Their adapters are way less expensive than comparable parts.

Steve

Reply to
steve_schefter

We have a US supplier with 200 pcs SN75518N in stock. Drop me a line at work if that would help snipped-for-privacy@xxx.plano.com remove the XXX

About 90% of the product sold from Shenzhen are duds, bad pulls, counterfeits or sub-standard remarks.

If you order from China you're better off to have your supplier just steal your money up front, that way you save the Fed Ex charges on the garbage they ship.

.
Reply to
-=Punkrat=-

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