OA1ZHA / TSZ121 precision amplifier

[Kevin A]

Posted on September 16, 2017 at 12:33

I'm not sure if I'm understanding the gain bandwidth correctly, but can I use OA1ZHA op amp for a signal with ADC sampling frequency of 2 kHz? or am I really limited to only 400 kHz based on maximum gain bandwidth? does ST make op amps with higher bandwidth? 

I have a biological signal that needs significant amplification, hence I will be using instrumental amplifier schematic as showed in fig 48 of the datasheet and set Rg to gain of about 500.   I read somewhere that bandwidth = gain x sampling frequency? Does that mean I can only amplify by a factor of 200?  400k = 200 x 2K?

or since I'm using configuration showed in fig 48, that equation doesn't apply?  I'm hoping that equation only applies for amplying using 1 op amp only? 

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[AvaTar]

Posted on September 18, 2017 at 11:36

Not sure if you are in the proper forum, but except for mentioning 'sampling frequency', there is no digital logic /MCU involved.

or since I'm using configuration showed in fig 48, that equation doesn't apply?  I'm hoping that equation only applies for amplying using 1 op amp only? 

Mentioned relation applies to every opamp, because it is composed of 'real' (non-ideal) components.

The higher the input frequency, the less the gain.

I'm not sure if I'm understanding the gain bandwidth correctly, but can I use OA1ZHA op amp for a signal with ADC sampling frequency of 2 kHz?

...

I have a biological signal that needs significant amplification,...

I didn't check the opamp's datasheet, but would expect a gain/bandwidth product of 10MHz or above.

That would be more than enough for your application.