The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: Chuck Simmons
Organization: You jest.
X-Mailer: Mozilla 4.61 [en] (X11; U; Linux 2.0.33 i586)
Subject: Re: Photodiodes in photovoltaic mode, speed considerations.
References: <3DACB831.F814C3D6@webaccess.net> <3DAD0481.A4004E95@NOSPAM.univ-lille1.fr> <3DAD0A0A.1F7BF2DD@webaccess.net> <firstname.lastname@example.org> <3DAD665D.41787E1A@webaccess.net> <email@example.com>
Date: Wed, 16 Oct 2002 15:11:11 GMT
NNTP-Posting-Date: Wed, 16 Oct 2002 08:11:11 PDT
Tony Williams wrote:
> In article <3DAD665D.41787E1A@webaccess.net>,
> Chuck Simmons wrote:
> > ........................................ The question is
> > predicting the speed of the diode given inadequate data
> I think you need to know the capacitance of each
> diode.... the sum of the C-stray plus the zero-
> -bias junction capacitance. Get the figure from
> the mfr, or where they bought the diode-die from.
> Or, (worst case), measure it yourself at a max
> stimulus of about 100mV peak.
The last is a very good suggestion I think. I can try it on some
photodiodes in the dead pile (the lasers are dead). Going to the mfr is
a waste of time. Only one has given us a BOM of their optics. They seem
to have figured out which side of the business we are on and don't feel
> Junction-C is a maximum at zero-bias, maybe more
> than 5x that at a reverse-bias above 10V.
> The simplest model (for small signals that do not
> induce significant diode conduction) is then of a
> current source (the photocurrent), in parallel with
> the shunt-C and the load resistor.
I'll try it. I think it will work.
... The times have been,
That, when the brains were out,
the man would die. ... Macbeth
Chuck Simmons firstname.lastname@example.org
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup