Re: Photodiode wich is fast enough to detect +50Mhz analog (sinus) signal??

From: Yannick (yannick_de_wit_at_pandora.be)
Date: 08/07/04 

Date: 7 Aug 2004 02:59:04 -0700

> Careful, using a sufficiently-wideband opamp can insure the summing-
> junction impedance will be low compared to the total shunt capacitance.
> Resistors have 0.05pF to 0.1pF of self capacitance, this should be your
> total feedback capacitance. With 3k resistor you'd have a -3dB rolloff
> at 530MHz. You want high R for low noise, so we'll try 100k, yielding
> a 16MHz rolloff. Then we can apply the standard R-C-R trick (this is
> more than 30 years old) to get a flat frequency response to 75MHz, or
> whatever you decide your bandwidth should be.
>

R-C-R trick to get a flat frequency responce, i never heard of this
before , can you explain how it works? is it butterworth filter
specification that you mean?

thanks,

Yannick

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