SMD Equivalents

[Paul E Bennett]

In updating an old design I find myself looking for some SMD equivalents to
old favourites.

The three components I need new parts for are:-

2N3904
2N3906
1N4004

I would prefer to get as close a spec to each device as is practicable.

In the meantime I shall be browsing the datasheets and selectors

--
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Paul E. Bennett IEng MIET.....<email://Paul_E....@topmail.co.uk>
Forth based HIDECS Consultancy.............<http://www.hidecs.co.uk>
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[k...@attt.bizz]

On Wed, 22 Jan 2014 18:26:58 +0000, Paul E Bennett
<Paul_E....@topmail.co.uk> wrote:

>In updating an old design I find myself looking for some SMD equivalents to
>old favourites.
>
>The three components I need new parts for are:-
>
> 2N3904

MMBT3904
> 2N3906
MMBT3906
> 1N4004
Do you really need 400V?

If so, the DiodesInc S1GB-13 might work.

>I would prefer to get as close a spec to each device as is practicable.
>
>In the meantime I shall be browsing the datasheets and selectors

Digikey has the best part selector in the market.

[miso]

Paul E Bennett wrote:

> In updating an old design I find myself looking for some SMD equivalents
> to old favourites.
>
> The three components I need new parts for are:-
>
> 2N3904
> 2N3906
> 1N4004
>
> I would prefer to get as close a spec to each device as is practicable.
>
> In the meantime I shall be browsing the datasheets and selectors
>

Funny thing about those old JEDEC numbers is some (if not all) specified the
package and electricals at the same time. So you can't make a surface mount
version of say a 1n914 because that diode has to be in the glass package. I
don't think it has to be in the clear glass, but just glass.

So if a surface mount part crossreferences to a JEDEC part, it is kind of
cheating if you want to nitpick.

[Paul E Bennett]

Thanks. I'll look those up. As to requiring 400V for the diodes, whilst that
part of the circuit would not normally see such a voltage it is in an
interface which could experience more than that as a trasnsient. The 1N4004
in the original circuit worked very well in the interfaces electrically
noisy and hostile environment.

[Lasse Langwadt Christensen]

Den torsdag den 23. januar 2014 01.18.52 UTC+1 skrev miso:
> Paul E Bennett wrote:
>
>
>
> > In updating an old design I find myself looking for some SMD equivalents
>
> > to old favourites.
>
> >
>
> > The three components I need new parts for are:-
>
> >
>
> > 2N3904
>
> > 2N3906
>
> > 1N4004
>
> >
>
> > I would prefer to get as close a spec to each device as is practicable.
>
> >
>
> > In the meantime I shall be browsing the datasheets and selectors
>
> >
>
>
>
> Funny thing about those old JEDEC numbers is some (if not all) specified the
>
> package and electricals at the same time. So you can't make a surface mount
>
> version of say a 1n914 because that diode has to be in the glass package. I
>
> don't think it has to be in the clear glass, but just glass.
>

hmm. http://www.vishay.com/docs/85557/ll4148.pdf

it's a 4148 I know, but it is smd and it is glass


-Lasse

[JW]

On Wed, 22 Jan 2014 16:18:52 -0800 miso <mi...@sushi.com> wrote in Message
id: <lbpn6g$9kj$1...@speranza.aioe.org>:

>Funny thing about those old JEDEC numbers is some (if not all) specified the
>package and electricals at the same time. So you can't make a surface mount
>version of say a 1n914 because that diode has to be in the glass package. I
>don't think it has to be in the clear glass, but just glass.

http://www.digikey.com/product-detail/en/1N914BWS/1N914BWSTR-ND/1873807

[John Devereux]

As our assemblers like to say, the reason the package is called SOD-80
is because it is a ****ing sod when you try to pick it up. Shoots out of
the tweezers across the room, rolls amazing distances on a table etc.

I started to design my very first SMD board using those (and the
"mini-melf" resistors in a similar package). Only because I liked the
familiar color bands on the resistors and the cathode marker on the
diodes.

Soon saw the light on that one. Couldn't read the colors anyway,
couldn't hold the parts.


--

John Devereux

[Klaus Bahner]

On 22-01-2014 19:26, Paul E Bennett wrote:
> In updating an old design I find myself looking for some SMD equivalents to
> old favourites.
>
> The three components I need new parts for are:-
>
> 2N3904

MMBT3904/PZT3904 (various manufacturers)

> 2N3906

MMBT3906/PZT3906 (various manufacturers)

> 1N4004

MRA4004 (On Semi)


Klaus

[miso]

Yes, but they don't call it a 1N4148 because that would be a leaded package.
That is my point. For the really old JEDEC parts, package and electricals
are the same.

The 1n914/1n4148 are considered free. Not free as in beer, but really free.
At least by old farts. But put them in surface mount, and they do have some
cost, especially in a leaded package. [I don't know about the SODs, but they
are a pain in the ass, at least for hand assembly.] The leaded package
probably costs more than the die.

Unless the part is sexy (low noise, low leakage, wide bandwidth, yada yada
yada), discrete semiconductors is an extremely low margin business.