LMP7721: High Speed Amplifier Application Notes

LMP7721 max IB at 125C is +/-5pA so if you used this part in your design how do you get 100pA? Please show your circuit schematic?
The input bias in CMOS op amps is caused by the reverse-bias leakage current of ESD protection diode, which may have opposite polarity; for that reason, it is not possible to cancel it.

Hello sir,

Thanks for the response.

I didn't use ESD protection diodes. Still I'm geting bias current.

The schematics of my Op Amp and the way i used for measuring Bias currents and its results are attached below.

Suggest me a way to reduce the bias current further.

Thanks in advance.

Sreehari

Hello Sir,

Sorry for the delay and Thanks for your response.

Is there any method to add some external circuitry to reduce the input bias current. Also I have to maintain high input impedance.

Thanks in Advance

Sreehari

Hi Sreehari,

I don't want to recommend this, but many many years ago when we had to decrease the input bias current of an OPAmp we have connected a high ohmic resistor from the input to the upper or lower supply voltage sometimes. But this will only work (if at all...), if the input voltage is nearly constant and if the input bias current does not show any relevant drift.

But why not using the LMP7721, as Marek already recommended?

Kai

Hello Sir,

Thanks for the another way which is not Recommended. On chip resistance may be difficult to manufacture. Why I'm not using LMP7721? The reason is, i just want to know how will be the internal circuitry, that's why i tried with simulation.

Thanks for your Precious time sir.
Sreehari