Cmos inverter - calculate gain

[Electricman2K5]

does anyone know how to calculate the gain from a cmos inverter such as a hex 4069 device. Ive seen people using them instead of op amps for gain..what are the advantages of this???????

 

[audioguru]

Hi Electricman,
A Cmos linear amplifier has a very high distortion at large output swings. With a very low level signal it works OK but is noisy.
Here is a description of them with typical gain:
https://www.electro-tech-online.com/custompdfs/2005/04/AN-88.pdf

 

[Russlk]

You calculate the gain same as an op amp: gain = Rf/Ri. The advantage is that you get 6 of them in a package. Keep in mind that the input and output are at about 1/2VCC.