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MicroBlocks

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Joined: 12/05/2012
Location: Thailand
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Posted: 10:20am 06 Aug 2013

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I am trying to find a good replacement for the old trusty 1n4148.
It has to be SMD.
They are used in the schematics for the colourMM VGA.

Does anyone know?

One important criteria, it must be obtainable. :)
Edited by TZAdvantage 2013-08-07

Microblocks. Build with logic.

kiiid

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Joined: 11/05/2013
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Posted: 12:26pm 06 Aug 2013

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what footprint do you need?

http://rittle.org

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MicroBlocks

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Posted: 01:14pm 06 Aug 2013

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0603 or bigger. I guess 1206 would be a normal size for that kind of part.
It would be nice if the package is flat so it can be picked up with a vacuum tip.
But i will be happy with anything at the moment because it is the through hole that is preventing me from getting it routed.
I was(am) tempted to use the axial version and solder it on an smd pad, but if the smd version can be bought for a reasonable price it would make it a lot easier and i have no problem to buy a reel if that is what is needed.

Edited by TZAdvantage 2013-08-07

Microblocks. Build with logic.

MicroBlocks

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Posted: 01:38pm 06 Aug 2013

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Lo and behold. I finally found a part number. PMLL4148L from philips/nxp.
Sometimes my google-fu is not what it used to be. Sigh.
Second task, getting them.

BTW Kiid, i hope you have used them before, are these glass round parts solderable or do they need special care. Datasheets say nothing about temperatures and no profiles for reflow. I was planning to use hot-air, and i hope they are not too sensitive. And for production i hope a pick&place can handle them.

Edited by TZAdvantage 2013-08-07

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kiiid

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Joined: 11/05/2013
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Posted: 02:15pm 06 Aug 2013

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Actually I haven't used them much. For packages this large I always prefer MBR130. Of course it depends on what do you need it for.
Recently I don't get to deal with 1206 and similar size parts very often...

http://rittle.org

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palcal

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Joined: 12/10/2011
Location: Australia
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Posted: 06:45pm 06 Aug 2013

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ALTRONICS have them in SOD323 package $2.90ea or by the reel.

Paul.

"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"

Bill.b

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Joined: 25/06/2011
Location: Australia
Posts: 225

Posted: 06:55pm 06 Aug 2013

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Jaycar IN914/IN4148 part No. ZR-1103 at AU$5.95 A bit dearer than the through the
hole part at AU$0.30 ea

Bill

In the interests of the environment, this post has been constructed entirely from recycled electrons.

Greg Fordyce
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Joined: 16/09/2011
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Posted: 09:47pm 06 Aug 2013

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TS4148RY is a flat part available from Farnell.

TS4148RY Edited by Greg Fordyce 2013-08-08

palcal

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Posted: 10:05pm 06 Aug 2013

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Yes, Element14 is the way to go they have 20 different flavours and they are cheap.

Paul.

"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"

centrex

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Joined: 13/11/2011
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Posted: 11:00pm 06 Aug 2013

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The JayCarr price is for a packet of 10.
cliff

Cliff

MicroBlocks

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Posted: 02:59am 07 Aug 2013

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Thanks guys.
I like the flat part from farnell, price is ok.
After a long search i also found SOD80 package (round) locally, but those are more difficult to handle for pick&place.
Now that i have more part numbers i can look more specific as i like to buy locally as much as possible. Otherwise it often incurs two times taxes, once for import, once for export.

Microblocks. Build with logic.

vegipete

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Joined: 29/01/2013
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Posted: 11:59am 07 Aug 2013

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I like using DigiKey's web site to search for interesting parts.

For example, searching for "4148" then looking at discrete diode, surface mount, in stock, gives me this page.

Brings up a nice list of contenders, including some 603's

Visit Vegipete's *Mite Library for cool programs.

bigmik

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Joined: 20/06/2011
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Posted: 07:46pm 07 Aug 2013

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Hi TZ,

I may have read this a bit late for you but a quick search on Element14 (Farnell) brings up a good selection of devices that are flat and will suit a vacuum picker...

Element14 list

They are fairly cheap (about 7c each in 100 QTY).,.

Regards,

Mick

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

MicroBlocks

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Posted: 08:56pm 07 Aug 2013

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If you change country to Thailand the price is 0.7 baht. That is a lot cheaper then the 7c, a big price difference (40 pieces instead of 14 for 1AU$), probably due to taxes paid in AU. Prices for quantities also not really change much if at all when Thailand is chosen. Weird....

Shipping costs and time, exchange rates and import to Thailand is always the culprit unfortunately.
Sometimes even 200% import duty, and that is not only over the cost of parts but also over the transport costs, it gets expensive really quick.

I now have even more part numbers to look for locally.
And if i can not succeed locally, at least i have a few options available.

Thanks!
Edited by TZAdvantage 2013-08-09

Microblocks. Build with logic.

robert.rozee
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Joined: 31/12/2012
Location: New Zealand
Posts: 2292

Posted: 09:53am 11 Aug 2013

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we used to use the BAT54 for just about everything at work (trimble at the time), a schottky device in a 3-pin package. was available in variants with just about every combination of pin-outs and just a couple of cents each. seemed to be the 'generic' smd small-signal diode, i see non-schottky variants exist too but at a higher price.

JohnS
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Joined: 18/11/2011
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Posted: 07:26am 12 Aug 2013

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Olimex use the BAT54 a lot!

John

kiiid

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Posted: 06:34pm 12 Aug 2013

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JohnS said Olimex use the BAT54 a lot!

Olimex is the indicator? Apple don't use BAT54 at all...
Edited by kiiid 2013-08-14

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JohnS
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Posted: 07:16pm 12 Aug 2013

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Apple may be a poor benchmark since they can afford to use devices in millions. I don't believe Olimex do and pretty sure no -one on here can do millions of units.

But if you know Apple use a suitable device that's cheap in small quantities what is it?

John

MicroBlocks

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Posted: 08:19pm 12 Aug 2013

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Locally only the BAT54 S is available, and that one has 2 diodes in series. I need the one that has them in parallel.
Until now i can only get the glass round version of the 4148 and i have some retailers looking for the TS4148 and the BAT54 C version, no answers yet.

Did one of you tried a BAT54 instead of a 1n4148 for the VGA signal?
Is it close enough to a 1n4148 to not change the colors or quality of the VGA signal?
Edited by TZAdvantage 2013-08-14

Microblocks. Build with logic.

TassyJim

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Joined: 07/08/2011
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Posts: 5915

Posted: 09:48pm 12 Aug 2013

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Using the BAT54 on the VGA output would give a very low output voltage compared to the 1N4148.
That would result in a very dull display.

Jim

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