When designing a PCB track, its width, length, and stack-up can introduce inherent inductance and capacitance. These parasitic elements can significantly impact the performance of sensitive circuits, such as a transimpedance amplifier. In my application, I want to carefully consider these factors to optimize the amplifier's performance and ensure signal integrity.

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My PCB is a 4-layer stack up (Signal-GND-Power-GND0), Would you please let me know what should be optimized track with for the connection of the ultrasound sensor to the inverting input of an amplifier and the output of the amplifier to the output connector? to reduce the PCB parasitic as much as possible?

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    \$\begingroup\$ Have you done some reasoning about how much parasitics (capacitance or inductance) your application tolerates, and if it is even necessary to consider making any optimizations? How long is the track? If an inch, would that be about 10pF? At the frequencies of interest, does it have an effect? Also, isn't the parasitics compensated by the 18pF feedback cap? If you are minimizing the trace parasitics, have you considered if the parasitics of the PCB pads are much larger than the trace? Just trying to understand, have you already considered the more obvious parasitics or not. \$\endgroup\$
    – Justme
    Commented Jul 8 at 15:32
  • \$\begingroup\$ @Justme Thank you for the comment. I will have 64 of these amplifiers, with each IC (OPA838) positioned differently in correspondence with the input and output connector. Consequently, the length of the tracks will vary for the input and output of each IC. Since the IC is highly sensitive to capacitance on the output, it is crucial to route the PCB to minimize capacitance as much as possible. That is why I would like to know how should I route them? (by which width 0.1,0.2,0.25) \$\endgroup\$
    – Andromeda
    Commented Jul 8 at 23:47


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