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WEBENCH® Active Filter Designer (Beta)

Active Filter Designs Within Minutes!

Active filters are vital in modern electronics; every data acquisition system needs them for bandwidth limiting signals before analog-to-digital converters as anti-aliasing filters, or after digital-to-analog converters as anti-imaging filters. Instrumentation relies on them for accurate signal measurements. Active filters are used for cutoff frequencies that range from sub-1Hz to 10MHz, where passive filter designs would require prohibitively large component values and sizes. Their design and verification can be tedious and time-consuming.

The WEBENCH Filter Designer lets you design, optimize, and simulate complete multi-stage active filter solutions within minutes. Create optimized filter designs using a selection of TI operational amplifiers and passive components from TI's vendor partners.

SELECT from low-pass, high-pass, band-pass, and band-stop filter types. Specify performance constraints for attenuation, group delay, and step response. Choose from a variety of filter responses such as Chebyshev, Butterworth, Bessel, transitional Gaussian to 6dB, transitional Gaussian to 12dB, linear phase 0.05°, linear phase 0.005°. Determine the filter response best suited for your design by optimizing for pulse response, settling time, lowest cost, pass-band ripple, and stop-band attenuation.

DESIGN your filter using Sallen-Key or Multiple Feedback topologies, select the best operational amplifiers for your design by evaluating gain bandwidth vs. current vs. cost and other parameters. Specify your resistor/capacitor tolerances between ideal, 0.5%, 1%, 2%, 5%, 10% and 20% values (E192, E96, E48, E24, E12, and E6). Experiment with user defined capacitor seed values. Optimize your filter topologies for sensitivity, lowest cost, and smallest footprint.

ANALYZE your design by running SPICE electrical simulation with closed-loop frequency response, step response, and sine-wave Response analysis options.

  

Step by Step:

Accessing WEBENCH Filter Designer

To access the WEBENCH Filter Designer application, click on the Filters tab.

  

Specify Filter Requirements

You can choose between a Lowpass, Highpass, Bandpass, or Bandstop filter. Specify your Attenuation and Flatness constraints for the filter.

  

 

Specify your Group Delay and Step Response constraints and click Start Filter Design to continue.

  

View/Optimize Filter Response Solutions

You will be presented with a page displaying the Filter Response solutions that meet your requirements. The Optimization Chart allows you to compare the performance parameters of each solution in a three dimensional format. The Performance Graphs allow you to compare the gain, phase, group delay, and step response performance for each of the solutions.

  

 

The Optimizer Knob allows you to optimize the solutions for pulse response, settling time, cost, passband ripple, and stopband attenuation. Modify your constraints and see the effects of the modifications immediately. Refine the results to narrow down on your desired filter response.

  

Optimizer Knob

Click on the Optimizer Knob and select the preferred optimization for your Filter Response solutions.

  

Modify Constraints

Modify your original constraints and click Recalculate to immediately see the results of those modifications.

  

Refine Results

Click and move the sliders to narrow down on the Filter Response choices that are displayed.

  

Optimization Graph

By default, the Optimization Graph shows Group Delay on the X axis, Attenuation on the Y axis, and Filter Order as the bubble size. Click on the axis configuration drop down to select an alternate parameter to display on the axis.

  

Performance Graphs

Compare the Gain, Phase, Group Delay, and Step Response performance between the recommended filter response solutions. Click on any of the graphs to expand full size.

  

Select a Filter Response

Select your desired Filter Response to continue.

  

Filter Topology Configuration

Now that you have selected your Filter Response, you can now configure your Filter Topologies. In this page, we have selected a 4th order Chebychev filter which is represented by two 2nd order Sallen Key stages. Each filter stage shows a schematic and a BOM as well as summary information about the filter stage. In the summary section, you can modify the gain.

  

Filter Topology Configuration

The Optimizer Knob allows you to optimize the Filter Topologies based on footprint, cost, or sensitivity. The Filter Topology Specification section allows you to select an alternate opamp, alternate filter topology, and specify seed and tolerance parameters for the passive components. You can tweak your design by selecting an alternate filter response or filter order.

  

Optimization Knob

Click on the Optimization Knob to optimize your Filter Topologies for smallest footprint, lowest BOM cost, or sensitivity.

  

Tweak Design

Select an alternate Filter Response and modify the Filter Order for you design.

  

Design Summary

Rename your design, add notes, and view the product folder for your selected opamp.

  

Filter Topology Specification

Select an alternate Filter Topology. Specify your Cap Seed and Cap/Res tolerances. Select an alternate opamp for your design.

  

Select Alternate OpAmp

Use the Optimization Charts to compare the performance parameters between the recommended opamps. Refine the results using the sliders. Select your alternate opamp from the list.

  

Update Gain

For each Filter Topology, you can view the summary information or modify the gain. Click Update to commit the changes.

  

View Component Values

By hovering over any of the passive components in a Filter Topology schematic, you can view the details for that component.

  

Bill of Materials

Each Filter Topology has a Bill of Materials associated with it. View the details of the components associated with the Filter Topology. Click Select Alternate Part to select an alternate component.

  

Select Alternate Part

View the alternate passive components and select an alternate.

  

Electrical Simulation

On the main navigation panel, click on the Sim button to enter Electrical Simulation.

  

 

Select the simulation that you would like to run. Simulation options are Closed Loop Freq Response, Sine Wave Response, and Step Response. Click on the input or output component to modify the stimulus. Click Start New Simulation to run the simulation.

  

 

View the simulation results on the right. The list of simulations you have performed are below the schematic. Click on the entry in the list to view the results for that simulation.

  

 

Click Waveform Controls to add or remove waveforms from your simulation results.

  

Feedback

Please submit feedback to http://webenchsupport.ti.com/support.

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