punch through devices

[mahak]

hi all,
can someone plz tell wat are punch through devices and wat is their
switchin speed and on state resistance

 

[Jamie]

hi all,
can someone plz tell wat are punch through devices and wat is their
switchin speed and on state resistance

I don't know about the switching speeds, You'd have to
check the spec's on them, But I use some nice diodes
that clamp very fast due to their design. TVS diodes is
one trade name they go by among others.
They make great replacements where circuits are using
zeners for protection. These units will react much faster
of course than a zener diode.

Look for TVS "Transient Voltage Suppresser" diodes.
the ones I use are punch through devices.. ..
You should be able to find some paper on it.

 

[Lostgallifreyan]

I don't know about the switching speeds, You'd have to
check the spec's on them, But I use some nice diodes
that clamp very fast due to their design. TVS diodes is
one trade name they go by among others.
They make great replacements where circuits are using
zeners for protection. These units will react much faster
of course than a zener diode.

Look for TVS "Transient Voltage Suppresser" diodes.
the ones I use are punch through devices.. ..
You should be able to find some paper on it.

I'm looking into those now on Google. Best find so far is this:
http://www.eettaiwan.com/ARTICLES/2001JUN/2001JUN14_AMD_AN2001.PDF?SOURCES=
DOWNLOAD
(beware wordwrap in that URL)

While I go on with this, there's one question I'm hoping I can get answered
faster here: Are TVS's enough like zener diodes that they can be used as
simple voltage regulators in the same way, but with the additional fast
surge suppression advantages that TVS's are intended for?

A secondary question, related to that: If they are useful as regulators, do
they also exist like zeners, with forward voltages as low as a volt or
less, so they can give crowbar protection against reverse polarity, in
conjunction with a fast fuse, something a standard zener is useful for?

 

[Jamie]

I'm looking into those now on Google. Best find so far is this:
http://www.eettaiwan.com/ARTICLES/2001JUN/2001JUN14_AMD_AN2001.PDF?SOURCES=
DOWNLOAD
(beware wordwrap in that URL)

While I go on with this, there's one question I'm hoping I can get answered
faster here: Are TVS's enough like zener diodes that they can be used as
simple voltage regulators in the same way, but with the additional fast
surge suppression advantages that TVS's are intended for?

A secondary question, related to that: If they are useful as regulators, do
they also exist like zeners, with forward voltages as low as a volt or
less, so they can give crowbar protection against reverse polarity, in
conjunction with a fast fuse, something a standard zener is useful for?

I've never used one for regulating but I can tell you that they respond
faster than a normal zener diode due the less capacitance and I don't
think the curve response is the same.

The main differences are the current handling and response time.

 

[Lostgallifreyan]

I've never used one for regulating but I can tell you that they
respond
faster than a normal zener diode due the less capacitance and I don't
think the curve response is the same.

The main differences are the current handling and response time.

Thankyou. If the curve response is sharp, then flat for a decent range if
currents in the low milliamps they might do ok. Any word on forward volts?
Only thing I know is it would have to be a unidirectional part, and I guess
it would then be a standard silicon 0.6V drop, but I haven't got one to
test, and I haven't yet seen a data sheet tell me what their forward
voltage is.