Transimpedance Amplifier PSoC 4200 BLE

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Hello, everyone I'm trying to interface the SFH7050 sensor which contains 3 LEDs and 1 Photodiode.

I need to calculate the value of the feedback capacitor (Cf). To do this I have the next equation:

datasheet.PNG

Rf is a value I can choose, C_d is on the datasheet so I need to figure out GBP and C_TIA from the PSoC's Op-amp Datasheet.

I've read it and I guess GBW_HI it's the GBP the equation mentions, am I right?
Plus I haven't been able to find the input capacitance of the Op-amp. Where can I find it?


Thanks

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1 Solution
Vasanth
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250 sign-ins 500 solutions authored First question asked

Hi ,

For the opamp as the output is taken through a GPIO pin, the pin input capacitance is the dominating factor in the capacitance value.

Best Regards,
Vasanth

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4 Replies
Vasanth
Moderator
Moderator
Moderator
250 sign-ins 500 solutions authored First question asked

Hi ,

For the opamp as the output is taken through a GPIO pin, the pin input capacitance is the dominating factor in the capacitance value.

Best Regards,
Vasanth

Is it the same value if I'm looking for the input capacitance of the V_minus pin of the Op-amp?

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Vasanth
Moderator
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250 sign-ins 500 solutions authored First question asked

Hi,

//Is it the same value if I'm looking for the input capacitance of the V_minus pin of the Op-amp?//

Yes, It is applicable for both the pins.

Best Regards,
Vasanth

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