Is the NJM2068 Op-amp good for use in active filters?

[Michael Weaser]

I was looking for op amps for use with making active filters, and I found the NJM2068 dual op amp , as looking at the specs it has a pretty high GBWP of 27 Mhz ,but there is an issue it warns in the datasheet. It says in the datasheet it can have oscillation issues if you use a Capacitive type load , but can be fixed by adding a resistor in series at the output.

 

[betwixt]

It depends on what frequency your active filters are filtering! Clues please.

Brian.

 

[LvW]

Most important: Which filter topology do you intend to use?

 

[d123]

Hi,

'Isolation resistor' is normal with most op amps if they will drive a capacitative load. Hint: I find that the gain/phase graph that is in most op amp datasheets brings me back to reality quickly when MHz GBW is described in the promotional blurb and the electrical specifications - my rule-of-thumb is to subtract a lot from the GBW number to guesstimate if it will still have any gain at all at 100Hz or even 10kHz...

 

[danadakk]

These might help -

https://ww1.microchip.com/downloads/en/DeviceDoc/adn003.pdf

Analog Filter Wizard Minimum GBW Calculation - Q&A - Amplifiers - EngineerZone

Hi, I am interested in knowing how the mimimum Gain Bandwidth Product is calculated for each stage in a filter chain within the Analog Filter Wizard. I understand

ez.analog.com

Your question has received a lot of attention in industry, especially when you are trying to do
high G, high Q, or wide BW filters in general. Extensive analysis has been done on this. There
are textbooks and many IEEE papers on this topic. Same for using a R on OpAmp output to de-
couple C load, and its impact on design.


Regards, Dana.

 

[Michael Weaser]

It depends on what frequency your active filters are filtering! Clues please.

Brian.

The frequencies are all in audio range, I need 10 filters, split between 0 to 7500 hz

 

[danadakk]

Do you need to handle 10 channels filtering them continuous time or
are you trying to detect signals in specific bands to trigger some activity,
based on the band the signal becomes active in ?


Regards, Dana.

 

[Michael Weaser]

Do you need to handle 10 channels filtering them continuous time or
are you trying to detect signals in specific bands to trigger some activity,
base don a band the signal becomes active in ?


Regards, Dana.

The filters are needed for a 10 band vocoder