# Op amp diode clipping

I am creating the following diode clipping circuit: The input signal, Vin, offset is removed and the signal is amplified using an op-amp. Then there are two diodes designed to clip the signal to +/- 0.7V. The clipped signal then goes to another op-amp, R4, where a gain and an offset are applied (not showed).

The diodes I have chosen are MBD701 and have a forward voltage of 0.7V at 10mA. The op-amp used is an AD4177 and is capable of outputting 25mA. I was wondering if I can use R3 to control the current across each Diode? My understanding is if the current across R3 is equal to 15mA and the op-amp outputs the max current of -25mA since the impedance of the diode is low in the forward direction, then -10mA will then leave the R3 and output node. If R4 impedance is very large, I can assume that almost all of the -10mA current will go across the diode. Is this logic valid or are the OP amps capable of outputting greater current than on the datasheet? Also is there a way to calculate the impedance of a diode?

Thank you

You might try this arrangement. Diodes can even be LEDs - you may not need a following amplifier. Resistors R1, R2 control diode current: 