Transimpeadance problem

[raptsoon]

Hi,
I am a newbie I need to do the following. Any suggestions as to how to proceed.
I need to design a two stage transimpedance amplifier using OPA355 with a gain of 6M and 400nSec rise time. with the following requirement:
Gain: 6M times (1nA will result in 6mV output)

Rise time: 400nsec worst case

Frequency response: 100KHz to 500KHz
Thx

 

[Grossel]

Hi.

Just do a regular calculation of U=RI. And I suggest you read this pdf file.

If source is a true current source (no dependent voltage) then cmr should not be an issue.

 

[raptsoon]

2 stage Transimpeadance

Thanks Grossel,

Here is my simple circuit and as stated earlier
I need a Gain: 6M times (1nA will result in 6mV output)
Rise time: 400nsec worst case
Frequency response: 100KHz to 500KHz

So I have calculated the resistor values arbitarily(R1,R2,R3) for producing a Gain of 6M.
I am having difficulty finding the capacitor values in order to maintain a 6M gain and also the rise time must be < 400 nsec.

I am a newbie and need help with the formulas in understanding this. I am ot sure if Iam missing out on some basic points.
I need to have the value of C2 without compromising the gain.

Please help me with this.
Thanks in advance