TI FilterPro Cheat Sheet

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2015-01-15 – Windoze 10 no longer plays well with TI FilterPro 🙁  The program will run but then lock up toward the results.  TI WeBench filter design tool is available on-line but still not as nice as the original.

Want to play with op amp filters?  The TI FilterPro Desktop (Version is a nice tool to quickly design filters with.  Note: You will need to register with TI in order to download the executable.

Overview:  http://www.ti.com/tool/filterpro&DCMP=hpa_amp_general&HQS=NotApplicable+OT+filterpro
Manual: http://www.ti.com/lit/an/sbfa001c/sbfa001c.pdf
Program: https://focus.ti.com/general/docs/event/accesseventaction.tsp?actionId=896
(Thank you Roy, K1LKY, for sending these updated links)


But below is a “cheat sheet” to quickly calculate values for the CALF.   Clicking on the screen shots will show a larger view.

In this example we will make a  4 pole 2.2KHz low pass filter using 2 op amp stages and an overall gain of 1:


From the File menu select New for a new design (by default it will start with a new design)


Select your filter type:  Click on Low Pass then click on the Next button.



Enter the following values:

Gain: 1 V/v  0dB  (unless you need amplification or attenuation)

Passband: 2200 Hz  – This is your cutoff frequency

Ripple: 1dB

Stopband: 5000 Hz

Stopband Attenuation: -45dB

Filter Order (AKA poles):

Check the Set Fixed box

Select 4 in the drop down.  This will set the design to a 4th order filter using 2 op amp stages (2 poles / stage).

Click Next


Select the filter type in the list at the bottom.  I usually like Bessel low Q type designs.  In this case select Bessel with a Q=.81 and click Next.



Select the Feedback type:

Select Multiple Feedback – Inverting (CALF) – my personal preference for designs

Other types for different designs:

Sallen Key – Non-inverting type

Multiple Feedback Fully Differential – Just as the complex name it describes.

Click Finish

You will be presented with a schematic, characteristic curves, BOM, etc.


At this point I will typically play with the standard tolerance values found in the upper right hand corner based on what is in my junk box.  Select 5% or 10% in the drop down for resistors and 20% for capacitors to begin with.  You can always narrow your results from there.

Adjust the R/C values.  For example, maybe I do not have 22nF & 56nF capacitors but plenty of 10nF.  Click on the “22nF” and 56nF values of  capacitor C1, change it to 10nF, and hit ENTER.  The other R/C values in that stage will change as needed.

TI-6a-Tolerances TI-6-Tolerance-Values


Finally from the File menu select Save Design.  Just in case you need to go back!


Try out your values on Spice or a breadboard, tweak as needed and enjoy your new filter!

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