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Science Forum Index » Electronics - Components Forum » high voltage PNP
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| Scott Seidman |
 Posted: Fri Apr 25, 2008 8:19 am |
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I can't seem to find any pnp transistors with a Vce bigger than 500V. I'd
like one that can go to 1K for use with a current sense. Any pointers??
--
Scott
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| legg |
| Posted: Fri Apr 25, 2008 10:48 am |
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On 25 Apr 2008 13:19:00 GMT, Scott Seidman
<namdiesttocs@mindspring.com> wrote:
Quote:
I can't seem to find any pnp transistors with a Vce bigger than 500V. I'd
like one that can go to 1K for use with a current sense. Any pointers??
Wrong decade, wrong technology. Think of another way.
If linearity is not required (ie limiting only) think of
amplitude-triggered communication methods. They aresimpler to develop.
RL |
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| Scott Seidman |
| Posted: Fri Apr 25, 2008 12:27 pm |
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legg <legg@nospam.magma.ca> wrote in
news:35v314dj3rukh98bta490ghnemueh61ode@4ax.com:
Quote: On 25 Apr 2008 13:19:00 GMT, Scott Seidman
namdiesttocs@mindspring.com> wrote:
I can't seem to find any pnp transistors with a Vce bigger than 500V.
I'd like one that can go to 1K for use with a current sense. Any
pointers??
Wrong decade, wrong technology. Think of another way.
If linearity is not required (ie limiting only) think of
amplitude-triggered communication methods. They aresimpler to develop.
RL
I'm trying to find a bigger transistor to use with the AD8212 High Voltage
Current Shunt Monitor. Adding the external transistor buys me a common
mode voltage capablility of Vce, totally braindead, but I can't find
anything greater than 500V.
--
Scott
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| Joerg |
| Posted: Fri Apr 25, 2008 1:01 pm |
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Scott Seidman wrote:
Quote: I can't seem to find any pnp transistors with a Vce bigger than 500V. I'd
like one that can go to 1K for use with a current sense. Any pointers??
Looks like the FMMT560 with 500V is pretty much the end of the rope when
it comes to commonly available parts. The IXTH10P60 goes to 600V but
it's a (largish and expensive) p-channel FET.
--
Regards, Joerg
http://www.analogconsultants.com/
"gmail" domain blocked because of excessive spam.
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| legg |
| Posted: Fri Apr 25, 2008 10:11 pm |
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On 25 Apr 2008 17:27:48 GMT, Scott Seidman
<namdiesttocs@mindspring.com> wrote:
Quote: I'm trying to find a bigger transistor to use with the AD8212 High Voltage
Current Shunt Monitor. Adding the external transistor buys me a common
mode voltage capablility of Vce, totally braindead, but I can't find
anything greater than 500V.
So you need linearity, huh.....?
Try sticking your AD8212 output collector's constant current through
the source of a p-channel fet, with the fet gate on the AD8212
'common' terminal. I assume you're getting well-decoupled power from
somewhere to run this thing. That should give current info over the
fet drain's compliance, if the added capacitance can be suffered at
the receiving end.
There are also methods of stringing 'transmitters' in series, with
their bases (or gates) on a HV divider. Each collector feeds an
emitter (or source) farther down the resistive divider.
Being brain dead isn't something you should be aiming to achieve,
despite what your boss tells you.
RL |
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