equivalent of LMP7721

[aliyesami]

this chip is too pricey , can you suggest me an equivalent chip that has ultra low bias current and does not need negative voltage and can run on 3.3v ?

thanks

P.S: I am trying to build this circuit

https://www.ti.com/lit/an/snoa529a/snoa529a.pdf

 

[schmitt trigger]

From the app note:

When deciding on an amplifier to use in this circuit, it is important to understand that
using an amplifier with a low bias current is of utmost importance. Selecting an amplifier with ultra-low bias
current such as TI's PowerWise LMP7721 3 fA input-bias-current precision amplifier is the best choice.

This, in addition to your 3.3 volt single supply requirement, means a premium opamp.

You may want to check the websites for Linear Technologies or Analog Devices, they will also have very high-performance opamps. But I'm afraid that they will be even pricier than TI's offerings.

- - - Updated - - -

Sometimes, when confronted with similar requirements, I have employed a low cost charge pump (ICL7660) to generate either a higher voltage or negative bias, and be able to use a cheaper opamp.