Re: really low power transistors

On Fri, 19 Dec 2008 18:49:06 -0800 (PST), mrdarrett@xxxxxxxxx wrote:

On Dec 19, 4:19 pm, Tim Wescott <t...@xxxxxxxxxxxxxxxx> 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)?


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

.

Relevant Pages

  • Re: really low power transistors
    ... the _collector_ to emitter voltage at saturation? ... Need to learn how to apply control theory in your embedded system? ... "Applied Control Theory for Embedded Systems" by Tim Wescott ...
    (sci.electronics.basics)
  • Re: really low power transistors
    ... the _collector_ to emitter voltage at saturation? ... Yes Zetex has about the best low VCE sat BJT's that I've found. ...
    (sci.electronics.basics)
  • Re: really low power transistors
    ... I did a mouser search but apparently Vbe sat. isn't a commonly specified ... Base to emitter voltage at saturation? ...
    (sci.electronics.basics)
  • Re: really low power transistors
    ... the _collector_ to emitter voltage at saturation? ... done in silicon. ...
    (sci.electronics.basics)