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The Bad Producer
Joined: Mar 08, 2009
Posts: 282
Location: The Manhole
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 Posted: Mon May 18, 2009 7:50 am Post subject:
SSM2210 Vs LM394
Subject description: ? |
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Hello,
I was wondering if these are substitutable for each other? I was about to buy some LM394's from Bridechamber, but I see he no longer (never did?!) stocks them, though he does have the SSM2210.
I've done a bit of research, but nothing to say "Yes, go ahead and swap",
any help would be most appreciated,
Thanks,
Charlie |
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softfin
Joined: Oct 11, 2006
Posts: 271
Location: Far in the north
Audio files: 1
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| Posted: Mon May 18, 2009 8:37 am Post subject:
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| It's an equivalent to lm394 and will work fine. |
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The Bad Producer
Joined: Mar 08, 2009
Posts: 282
Location: The Manhole
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| Posted: Mon May 18, 2009 9:44 am Post subject:
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Thank you Softfin,
I thought they might be, and I'd looked at the datasheets, but it helps to be sure!
Thank you,
Charlie |
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ultrashock
Joined: Dec 10, 2009
Posts: 40
Location: Vienna.AT
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| Posted: Wed Sep 22, 2010 8:29 am Post subject:
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the time goes on... and now on the analog.com site the SSM2210 are NO LONGER available.
The nearest solution from AD is the full substitute SSM2212 (I observed it more expensive by my local dealer's prices. at the same time the ssm2210 are out of stock but there are some at $9 price per unit in another dealer (which is actually, afwul).
the ssm2210 are also out of stock at digikey as well as BCM847
p.s.: are there any other matched pairs alternatives today? |
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marctims
Joined: Feb 19, 2009
Posts: 5
Location: netherlands
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| Posted: Wed Sep 22, 2010 8:39 am Post subject:
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| two hand matched 2N3904 NPNs will work. |
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softfin
Joined: Oct 11, 2006
Posts: 271
Location: Far in the north
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| Posted: Wed Sep 22, 2010 11:14 am Post subject:
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| marctims wrote: | | two hand matched 2N3904 NPNs will work. |
Or any general purpose NPNs for that matter. 
But... those LM394s and SSM2210s etc. are not only hfe matched but also vbe matched if I remember right. So, depending on application lm394s might work better, for example in a differential pair based mic preamp.
For most synth related applications simply hfe matched will be enough as far as I know. |
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Sebo
Joined: Apr 27, 2007
Posts: 564
Location: Argentina
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| Posted: Wed Sep 22, 2010 4:40 pm Post subject:
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For VCOs exponential converters the transistor pair have to be Vbe matched.
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Sebo
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My Music:
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softfin
Joined: Oct 11, 2006
Posts: 271
Location: Far in the north
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| Posted: Thu Sep 23, 2010 2:35 am Post subject:
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| Sebo wrote: | | For VCOs exponential converters the transistor pair have to be Vbe matched. |
You're right. So Vbe matching is more important than hfe matching in most cases after all. |
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gwaidan
Joined: Mar 07, 2009
Posts: 53
Location: Sydney, Australia
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Posted: Fri Sep 24, 2010 4:03 am Post subject:
Re: SSM2210 Vs LM394
Subject description: ? |
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| The Bad Producer wrote: | Hello,
I was wondering if these are substitutable for each other? I was about to buy some LM394's from Bridechamber, but I see he no longer (never did?!) stocks them, though he does have the SSM2210.
I've done a bit of research, but nothing to say "Yes, go ahead and swap",
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from what I know, you should be fine to sub the ssm2210. Strife tends to come in the opposite direction, as the LM394 wasn't designed to drive high currents and as a result can cause expo conversion circuits that need to drive more than 1mA to go flat at the high end- Ray Wilson recommends using the SSM2210 over the LM394 in the MFOS VCO for this reason |
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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| Posted: Fri Sep 24, 2010 4:34 am Post subject:
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| Sebo wrote: | | For VCOs exponential converters the transistor pair have to be Vbe matched. |
Actually, for expo converters matching is not all that critical. Matching just provides part of the needed temperature compensation by cancelling the prefactor of the exponent. Log conformance is more important, which is why 2N3904 pairs aren't all that great (depending on how much you care about tracking).
Matching is crucial for differential pairs -- just try making a discrete OTA!
Ian |
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The Bad Producer
Joined: Mar 08, 2009
Posts: 282
Location: The Manhole
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| Posted: Fri Sep 24, 2010 5:18 am Post subject:
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Obviously I'm not super learned on all this, but the high cost and (slight) difficulty in sourcing matched transistor packages, has led me to think about trying Ray Wilsons matching circuit,
here
I'll have to do a bit of reading to understand what you are saying Ian (and even then would probably fall short of totally getting it!), but are you suggesting that hand matching transistors is not a good idea, or just not good for certain applications?
Charlie
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frijitz
Joined: May 04, 2007
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Location: NM USA
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The Bad Producer
Joined: Mar 08, 2009
Posts: 282
Location: The Manhole
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| Posted: Fri Sep 24, 2010 8:08 am Post subject:
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Thanks for posting that Ian - the clarification too.
I guess the 12V needs to be pretty accurate? also the diode, could I use a 4148 there? Looks really nice and simple!
I also noticed dingebre is producing a transistor matching board along with the other Steiner Synthasystem modules:
http://www.xmission.com/~dingebre/Trans_Match.html
Have you seen that one?
Charlie
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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| Posted: Fri Sep 24, 2010 8:51 am Post subject:
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| The Bad Producer wrote: | | I guess the 12V needs to be pretty accurate? |
No, that's not critical at all.
| Quote: | | also the diode, could I use a 4148 there? Looks really nice and simple! |
Yes, any ole Si signal diode. It holds the collectors at about .65V, just to keep the devices out of saturation. I like to match at a small collector voltage, because I usually use the opamp integrator method in my Saw VCOs, where the collector is at virtual ground.
| Quote: | | I also noticed dingebre is producing a transistor matching board along with the other Steiner Synthasystem modules: |
Right. That is the original Moog circuit (with the obvious error corrected). He just goes ahead and runs it at 12V instead of 10V. This merely sets the test current at 120uA instead of 100uA. 
You don't need fancy circuits for any of this. You are just matching the transistors, not making laboratory-accuracy measurements of anything.
Ian |
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The Bad Producer
Joined: Mar 08, 2009
Posts: 282
Location: The Manhole
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| Posted: Fri Sep 24, 2010 9:03 am Post subject:
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| frijitz wrote: | .......You don't need fancy circuits for any of this. You are just matching the transistors, not making laboratory-accuracy measurements of anything.
Ian |
Ha ha, that's good to know! For some reason I'd regarded it as a complex and arcane art, that is why I'd avoided it - or rather not 'dealt' with it yet...
Thanks again Ian...
Charlie
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piedwagtail
Joined: Apr 15, 2006
Posts: 297
Location: shoreditch
Audio files: 3
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| Posted: Fri Sep 24, 2010 10:40 am Post subject:
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I found the SSM2210/2220s failed easily.
I just jammed 2n390xs into the dil sockets when I'd read Arp never matched anything.
Arp 4072 filter/Thomas Henry triangle core vco.
Robert.
SSM2017s fail easily too! |
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dugernaut
Joined: Jul 24, 2009
Posts: 50
Location: New Jersey
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| Posted: Sun Dec 12, 2010 6:46 pm Post subject:
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| What about the old CA3046? 5 transistors on a single chip. They're still available and fairly cheap. |
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adambee7
Joined: Apr 04, 2009
Posts: 420
Location: united kingdom
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| Posted: Sun Dec 12, 2010 7:00 pm Post subject:
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| or the "THAT300" series? |
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adambee7
Joined: Apr 04, 2009
Posts: 420
Location: united kingdom
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| Posted: Sun Dec 12, 2010 7:16 pm Post subject:
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| But the THAT300 and CA3046 are 14DIP. so if your building a vco from scratch id use these. But for a direct replacement for LM394 or SSM2210 I would match some genereal NPNs. With a decent Digital Meter and Ians matching circuit you could match Vbe of +/-500uV. I normally do 1mV ish |
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dugernaut
Joined: Jul 24, 2009
Posts: 50
Location: New Jersey
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| Posted: Wed Dec 15, 2010 4:37 pm Post subject:
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I just looked at Digikey's catalog and there are several surface mount SMT matched pairs for under $0.25 !!! If someone is making a new design and don't mind a little SMT work, that's probably a great option. It should also be possible to make a little adapter board to make it fit in a 394 / 2210 PCB layout.
Does anyone know if there's anything else that makes the 2210 / 394 special that would keep these SMT guys from working? Ian? |
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frijitz
Joined: May 04, 2007
Posts: 1734
Location: NM USA
Audio files: 54
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| Posted: Wed Dec 15, 2010 5:53 pm Post subject:
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| dugernaut wrote: | I just looked at Digikey's catalog and there are several surface mount SMT matched pairs for under $0.25 !!!
Does anyone know if there's anything else that makes the 2210 / 394 special that would keep these SMT guys from working? |
Folks have been concerned that those pairs are not monolithic (on the same substrate). But i've been told they work OK. Their log conformance and noise figure aren't as good as those of the supertransistors, so it depends on how concerned you are with accurate tracking.
Ian |
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