really low power transistors

Guest
Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly
specified parameter... ?

Thanks,

Michael
 
On Fri, 19 Dec 2008 13:45:04 -0800 (PST), mrdarrett@gmail.com wrote:

Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly
specified parameter... ?

Thanks,

Michael
Click to expand...
Most any npn will do that at low current.

John
 
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message
news:206ok4hp2aiub5ue9cidhs7glou1p44ja7@4ax.com...
On Fri, 19 Dec 2008 13:45:04 -0800 (PST), mrdarrett@gmail.com wrote:

Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly
specified parameter... ?

Thanks,

Michael

Most any npn will do that at low current.

John
Click to expand...
Either the OP has got the terms mixed up or wants a germanium transistor.
 
On Dec 19, 2:11 pm, "ian field" <gangprobing.al...@ntlworld.com>
wrote:
"John Larkin" <jjlar...@highNOTlandTHIStechnologyPART.com> wrote in message

news:206ok4hp2aiub5ue9cidhs7glou1p44ja7@4ax.com...

On Fri, 19 Dec 2008 13:45:04 -0800 (PST), mrdarr...@gmail.com wrote:

Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly
specified parameter... ?

Thanks,

Michael

Most any npn will do that at low current.

John

Either the OP has got the terms mixed up or wants a germanium transistor.
Click to expand...

Yeah, low power isn't necessarily equal to low Vbe_sat, but I figured
a 0.1Vbe_sat transistor wouldn't be an output transistor in a 100W
audio amplifier anyway...

Thanks.

Michael
 
mrdarrett@gmail.com wrote:
Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?
....
Click to expand...

What a coincidence - I just subscribed here to ask that exact question.
Well, my question's a little more complicated, so I'll do another
thread for it.

As to your question - I found low Vcesat ... oh, wait - you wanted low
V_be_sat. Or did you? Anyhow, ON Semi has SMT BJT's down to 50 mv Vcesat:
http://www.onsemi.com/PowerSolutions/parametrics.do?id=808

HTH,
Bob
 
"John Larkin"
mrdarrett@gmail.com wrote:
Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly
specified parameter... ?


Most any npn will do that at low current.
Click to expand...

** You didn't read the question.

The trolling fool wants Vbe sat to be impossibly low.



.... Phil
 
mrdarrett@gmail.com wrote:
Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly
specified parameter... ?

Thanks,

Michael
When I don't have that info in front of me, I usually go for a
Click to expand...
low Vceo range, the Vsat is normally lower.

Your search is average for a unit in the 20 Vceo range.

http://webpages.charter.net/jamie_5"
 
On Fri, 19 Dec 2008 13:45:04 -0800, mrdarrett wrote:

Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly specified
parameter... ?

Thanks,

Michael
Click to expand...
Base to emitter voltage at saturation?

Or do you mean Vce_sat, the _collector_ to emitter voltage at saturation?

Zetex and others make the latter in small sizes. The former can't be
done in silicon.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
 
mrdarrett@gmail.com wrote:

Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?
Click to expand...
Vbe ?

Do you mean Vce ? Shouldn't be a problem. 2N4401 2N4403 are very low
IIRC. Mind you @ what current ? You're really not supplying enough info.

Graham
 
mrdarrett@gmail.com wrote:

On Dec 19, 2:11 pm, "ian field" <gangprobing.al...@ntlworld.com
wrote:
"John Larkin" <jjlar...@highNOTlandTHIStechnologyPART.com> wrote in message

news:206ok4hp2aiub5ue9cidhs7glou1p44ja7@4ax.com...

On Fri, 19 Dec 2008 13:45:04 -0800 (PST), mrdarr...@gmail.com wrote:

Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly
specified parameter... ?

Thanks,

Michael

Most any npn will do that at low current.

John

Either the OP has got the terms mixed up or wants a germanium transistor.

Yeah, low power isn't necessarily equal to low Vbe_sat, but I figured
a 0.1Vbe_sat transistor wouldn't be an output transistor in a 100W
audio amplifier anyway...
Click to expand...
You're talking nonsense.

Graham
 
Bob Engelhardt wrote:

mrdarrett@gmail.com wrote:
Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?
...

What a coincidence - I just subscribed here to ask that exact question.
Well, my question's a little more complicated, so I'll do another
thread for it.

As to your question - I found low Vcesat ... oh, wait - you wanted low
V_be_sat. Or did you? Anyhow, ON Semi has SMT BJT's down to 50 mv Vcesat:
http://www.onsemi.com/PowerSolutions/parametrics.do?id=808
Click to expand...
Yup 50mV is no trouble.

Graham
 
On Fri, 19 Dec 2008 18:19:00 -0600, Tim Wescott <tim@seemywebsite.com>
wrote:


Base to emitter voltage at saturation?

Or do you mean Vce_sat, the _collector_ to emitter voltage at saturation?

Zetex and others make the latter in small sizes. The former can't be
done in silicon.
Click to expand...
Yes Zetex has about the best low VCE sat BJT's that I've found. The
FMMT491 and FMMT618 to name two.

Onsemis got a couple too the NSS40201LT1G and the NSS40301MZ4 they're
a little pricey though.
 
On Dec 19, 4:19 pm, Tim Wescott <t...@seemywebsite.com> wrote:
On Fri, 19 Dec 2008 13:45:04 -0800, mrdarrett wrote:
Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly specified
parameter... ?

Thanks,

Michael

Base to emitter voltage at saturation?
Click to expand...

Yes, that.


Or do you mean Vce_sat, the _collector_ to emitter voltage at saturation?
Click to expand...

No, not that.

Zetex and others make the latter in small sizes. The former can't be
done in silicon.
Click to expand...

Ah.

Mr. Larkin had an interesting idea. If I wanted to say power a boost
converter (0.1 V to 1V) could I just feed the 0.1V to the base of my,
eh, 2N3904 NPN and it would work (at just incredibly low efficiency,
since it's not in saturation)?

Thanks,

Michael
 
On Dec 19, 5:31 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:
mrdarr...@gmail.com wrote:
Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

Vbe ?
Click to expand...

Yes.

Do you mean Vce ?
Click to expand...

No.

Shouldn't be a problem. 2N4401 2N4403 are very low
IIRC. Mind you @ what current ? You're really not supplying enough info.

Graham
Click to expand...

@ < 100 mA. Not expecting much @ 0.1V.

Actually the 0.1V was kind of optimistic, come to think of it...

Michael
 
On Fri, 19 Dec 2008 22:11:39 -0000, "ian field"
<gangprobing.alien@ntlworld.com> wrote:

"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message
news:206ok4hp2aiub5ue9cidhs7glou1p44ja7@4ax.com...
On Fri, 19 Dec 2008 13:45:04 -0800 (PST), mrdarrett@gmail.com wrote:

Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly
specified parameter... ?

Thanks,

Michael

Most any npn will do that at low current.

John


Either the OP has got the terms mixed up or wants a germanium transistor.
Click to expand...
Oops, I was thinking Vce. Even a germanium won't do that low a Vbesat.

What does Vbesat mean anyhow?

We're using some cool phemts (gaas fets) that are, like, 4 ohms Rdson
at zero gate voltage, and essentially off at -0.5.

John
 
On Fri, 19 Dec 2008 18:49:06 -0800 (PST), mrdarrett@gmail.com wrote:

On Dec 19, 4:19 pm, Tim Wescott <t...@seemywebsite.com> wrote:
On Fri, 19 Dec 2008 13:45:04 -0800, mrdarrett wrote:
Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly specified
parameter... ?

Thanks,

Michael

Base to emitter voltage at saturation?


Yes, that.



Or do you mean Vce_sat, the _collector_ to emitter voltage at saturation?


No, not that.

Zetex and others make the latter in small sizes. The former can't be
done in silicon.


Ah.

Mr. Larkin had an interesting idea. If I wanted to say power a boost
converter (0.1 V to 1V) could I just feed the 0.1V to the base of my,
eh, 2N3904 NPN and it would work (at just incredibly low efficiency,
since it's not in saturation)?
Click to expand...
0.1 volts on the base of a bipolar wouldn't do much of anything.

A 0.1 volt input boost converter would be a challenge. The easy way
would be to bootstrap it with a battery. Or a solar cell.

You might be able to make an oscillator, at 0.1 volts, from a
depletion-mode gaasfet. Maybe.

Too bad you can't get tunnel diodes any more.

John
 
In article <7ssok4d63natk0s5thstc289ch0a35gs85@4ax.com>,
jjlarkin@highNOTlandTHIStechnologyPART.com says...
On Fri, 19 Dec 2008 22:11:39 -0000, "ian field"
gangprobing.alien@ntlworld.com> wrote:


"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message
news:206ok4hp2aiub5ue9cidhs7glou1p44ja7@4ax.com...
On Fri, 19 Dec 2008 13:45:04 -0800 (PST), mrdarrett@gmail.com wrote:

Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly
specified parameter... ?

Thanks,

Michael

Most any npn will do that at low current.

John


Either the OP has got the terms mixed up or wants a germanium transistor.


Oops, I was thinking Vce. Even a germanium won't do that low a Vbesat.

What does Vbesat mean anyhow?
Click to expand...
Vbe with collector open?

We're using some cool phemts (gaas fets) that are, like, 4 ohms Rdson
at zero gate voltage, and essentially off at -0.5.

John
Click to expand...
--
Keith
 
On Fri, 19 Dec 2008 18:49:06 -0800, mrdarrett wrote:

On Dec 19, 4:19 pm, Tim Wescott <t...@seemywebsite.com> wrote:
On Fri, 19 Dec 2008 13:45:04 -0800, mrdarrett wrote:
Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly
specified parameter... ?

Thanks,

Michael

Base to emitter voltage at saturation?


Yes, that.



Or do you mean Vce_sat, the _collector_ to emitter voltage at
saturation?


No, not that.

Zetex and others make the latter in small sizes. The former can't be
done in silicon.


Ah.

Mr. Larkin had an interesting idea. If I wanted to say power a boost
converter (0.1 V to 1V) could I just feed the 0.1V to the base of my,
eh, 2N3904 NPN and it would work (at just incredibly low efficiency,
since it's not in saturation)?

You probably won't be able to detect the difference in collector current
Click to expand...
between Vbe = 0 and Vbe = 0.1, at least with a Silicon transistor. Even
a Germanium transistor really needs a Vbe of around 0.3V. So there's not
much difference here between using a 2N3904 and a lump of clay.

You ask for the impossible. Explain what you _really_ want to do, and
someone may be able to help you out.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
 
mrdarrett@gmail.com wrote:
On Dec 19, 4:19 pm, Tim Wescott <t...@seemywebsite.com> wrote:

On Fri, 19 Dec 2008 13:45:04 -0800, mrdarrett wrote:

Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly specified
parameter... ?

Thanks,

Michael

Base to emitter voltage at saturation?



Yes, that.



Or do you mean Vce_sat, the _collector_ to emitter voltage at saturation?



No, not that.


Zetex and others make the latter in small sizes. The former can't be
done in silicon.



Ah.

Mr. Larkin had an interesting idea. If I wanted to say power a boost
converter (0.1 V to 1V) could I just feed the 0.1V to the base of my,
eh, 2N3904 NPN and it would work (at just incredibly low efficiency,
since it's not in saturation)?

Thanks,

Michael
Click to expand...
No, it wouldn't work at all, unless what you have in
mind is different than what you seem to be saying.
Give us a schematic of what you are thinking about.

Ed
 
On Dec 19, 8:59 pm, Tim Wescott <t...@seemywebsite.com> wrote:
On Fri, 19 Dec 2008 18:49:06 -0800, mrdarrett wrote:
On Dec 19, 4:19 pm, Tim Wescott <t...@seemywebsite.com> wrote:
On Fri, 19 Dec 2008 13:45:04 -0800, mrdarrett wrote:
Anyone recommend any NPN transistors with around 0.1-0.3VBE sat. ?

I did a mouser search but apparently Vbe sat. isn't a commonly
specified parameter... ?

Thanks,

Michael

Base to emitter voltage at saturation?

Yes, that.

Or do you mean Vce_sat, the _collector_ to emitter voltage at
saturation?

No, not that.

Zetex and others make the latter in small sizes. The former can't be
done in silicon.

Ah.

Mr. Larkin had an interesting idea. If I wanted to say power a boost
converter (0.1 V to 1V) could I just feed the 0.1V to the base of my,
eh, 2N3904 NPN and it would work (at just incredibly low efficiency,
since it's not in saturation)?

You probably won't be able to detect the difference in collector current
between Vbe = 0 and Vbe = 0.1, at least with a Silicon transistor. Even
a Germanium transistor really needs a Vbe of around 0.3V. So there's not
much difference here between using a 2N3904 and a lump of clay.

You ask for the impossible. Explain what you _really_ want to do, and
someone may be able to help you out.
Click to expand...

Funny. I would have thought they are common. Guess I was wrong.

Anyhow... I was thinking of making some sort of super-tiny electric
generator (basically just a magnet loosely moving inside a coil of
wire), and boosting that up to, oh, 1 volt or so, to light up an LED.
Another challenge would be to rectify the tiny current... guess I
can't use normal diodes (0.7V drop... oh well...)

Michael
 
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