WEBENCH® Tools: Filter Design Tool

James Edgar

Tool/software: WEBENCH® Design Tools

The Filter Design Tool is very good but is there a reason why the MFB topology only allows gains of 1 or greater. I need to add some attenuation in my signal path to match an ADC input range so will have to add another stage. Is there a way to achieve a design with gain <1?

over 6 years ago

0 Alfred Chong over 6 years ago

TI__Expert 3482 points

James,

The Filter Design Tool allows MFB design to be less than 1 dB as long as it is a positive number.

As shown in below figure, I specified the gain to be 0.5dB and it displayed as 1.059 V/V. In fact, when you specify a gain that is less than 1dB,

MFB topology will be chosen by default.

Regards,

Alfred

0 James Edgar over 6 years ago in reply to Alfred Chong

Prodigy 20 points

Hi Alfred,

Thanks for your quick reply. In fact, to achieve a gain of less than unity, I need to be able to enter a negative number in dB's (ie. less than zero), or a V/V value of less than 1. Is this possible?

Regards, James

0 Alfred Chong over 6 years ago in reply to James Edgar

TI__Expert 3482 points

James,

Currently, it is not possible as the UI limits the minimum gain to be 1 V/V

Thanks for your feedback and we will add this into our backlog for future improvement!

Regards,

Alfred

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WEBENCH® Tools: Filter Design Tool