OPA657_with_Photodiode

Wilson silva

My name is Wilson

In the figure below, the photodiode must be replaced by another whose capacitance is 70 pF.
What should be the new values of the capacitor and resistor?

Thanks for the help

over 14 years ago

0 Luke LaPointe over 14 years ago

TI__Genius 13335 points

Hello Wilson,

The formula for compensating the amplifier can be derived from the equation on page 11 of the datasheet.

1/(2π*R_F*C_F)= sqrt(GBP /(4π*R_FC_D))

Using the following conditions given in the datasheet, R_F=200kΩ,C_D = 5.2pF + 70pF, GBP=1600MHz

Solve for C_F and get 0.27pF.

Regards,
Luke

0 Wilson silva over 14 years ago in reply to Luke LaPointe

Prodigy 20 points

Hi Luke,

Thanks for help me

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OPA657_with_Photodiode