GAAS chips overvoltage protection

S

Slav Mitrofanov

Guest
Good day, dear community. There is a little problem and hope someone may
guide me to a solution. I have got active antennas switced by a GAAS chips
(like HMC336MS86 or SW338) I want the chips be protected from ESD and
probably wrong conection (between devices wich may have different woltage at
their GND pins. There are two solutions I have got:: back reversed diodes
and special 0603 SurgeX devices from Cooper Bussman.But the trigger voltage
for them is 100V and clamping voltage is 35 V. Will it protect my chips? Can
anyone recommend me a literature to read? Datasheets for thechips limits
only the max power, not voltage...
Thanks in advance.
Slav
 
Hi Slav,

The usual method of one diode to the supply and one to ground might work. You
can get fast double diodes in SOT23 pack so you'd only need one device. It
depends on what input levels can be tolerated.

Back to back diodes can introduce intermodulation if this is a receiver circuit.

Regards, Joerg

http://www.analogconsultants.com
 
Hello, Joerg!

Thanks for replying. Sometimes a simple question might be a problem. In this
case I just have a huge desire to use the new (for me) component - the
COOPER Bussmann ESD 0603eESDA SurgeX technology) It is just one 0603 chip
which has 0.2 pF capacity and extra high resistance. at the 100 V it
triggers and in 5 nS the voltage is around 35V. I just do not know if that
is ok for the chips I mentioned.

Thanks for the information about your site. Have a brief look at it . Hope
one day will apply officially for help.

Best regards.

Slav.
p.s. Sorry e-mail you mentioned is not available for my provider.


"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:40B13928.B78F7F6E@removethispacbell.net...
Hi Slav,

The usual method of one diode to the supply and one to ground might work.
You
can get fast double diodes in SOT23 pack so you'd only need one device. It
depends on what input levels can be tolerated.

Back to back diodes can introduce intermodulation if this is a receiver
circuit.

Regards, Joerg

http://www.analogconsultants.com
Click to expand...
 
Hi Slav,

Just make sure that these remaining surges are ok with your GAAS chips. I don't
know the Bussman devices but a remaining 35V after 5nsec (that's a really long
time for GAAS) could be too much. Best is to check the data sheet for absolute
maximum ratings. But again, it could be that 5nsec of surge is still too much
and this could damage the chips. Sometimes that damage is partial which means
the GAAS chips might still work but not up to specification anymore. That is
like in a boxing ring where the chips get hit again and again, become worse in
performance over time and after too many hits they'll give up.

A nice pair of Schottky diodes is usually best but of course that will add
capacitive load.

Email: Just delete the parts "notthis" and "removethis" and it'll work. Or use
the one on my web site. Sorry for that but it is about the only way to avoid all
this junk email from people selling medicine and other stuff that I don't need.

Regards, Joerg

http://www.analogconsultants.com
 
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