Your 1st circuit with the opamp circuit - that is positive feedback. Also, I am unclear how you expect the circuit to work.
Your 2nd circuit is open-loop...may not be the most optimum stable solution.
Here is a potential closed-loop opamp solution. For…
Hi Jason,
I'm suspecting that your compensation capacitor C F (or C1 in your case shown with TINA-TI) is too large at 3pF. Going by OPA847 datasheet Equation 1 on page 11, C F = 1.8pF (with CD=~50pF). So, you might be band-limiting yourself and not realizing…
Other Parts Discussed in Thread: OPA842 Hi,
I believe somewhere that TI had a recommended replacement for the OPA642.
Cant seem to find this. Any help is appreciated.
Tim
Thomas,
The OPA846 is not unity gain stable and will most likely oscillate if constructed as shown. This is probably causing a problem for the simulator. The OPA842 is the same basic amplifier that is compensated for untiy gain operation.
Another thing…
The GBP definition, and what you need for TIA design, is the single pole projection to 0dB. Get that by going to the Aol=40dB point and multiplying that frequency by 100X, 1.59GHz here,
This recent article tries to explain this confusion, and also some…
Part Number: OPA846 I need to edit this curve, any idea what software created this and perhaps that source file?
Slide 10 in this document,
7532.Transimpedance design flow using high speed op amps.pptx