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Slew Rate, Bandwidth, Settling time, rise time for high speed transipmedance amp
arivalagan13:
Hi all
I'm in the process of designing a Transimpedance amplifier for an analytical instrument. The sample waveform (hand-drawn) is attached in the attachments. The requirement is to amplify a pulse kind of signal whose maximum amplitude is around 700 nA and the width of the pulse is around 1 ns. So, I need a high-speed transimpedance amplifier.
My question is what are the opamp parameters that decide the speed of the amplifier. I need a concrete relationship between slew rate, settling time, rise time, bandwidth/gain-bandwidth. And particular to the signal which parameter is most important so that I can choose the right opamp for the design.
Regards
M Arivalagan
Marco:
What's the source capacitance? TI has a reference design for a 200 MHz TIA with a link to a reference how to calculate the necessary GBP.
Personally though I'd try to dig up some old stock for MAX3266CSA, one of the few GHz range TIAs available in non-die form.
arivalagan13:
The source capacitance is around 20pF
Marco:
Really? That's kinda huge for something with a GHz worth of bandwidth and will present an almost insurmountable challenge to any opamp and TIA you can get in a solderable package.
awallin:
that one seems close(ish) to 1GHz:
http://www.ti.com/lit/ug/tidud08/tidud08.pdf
it might use this photodiode, specified as 2 pF (with some reverse bias)
https://acphotonics.com/downloads/High_Speed_800nm_900nm_PIN_Photodiode.pdf
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