Sanity check of TI reference design calculations

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Hi all,

 

I'm currently working with a Texas Instruments reference design, and would appreciate a second pair of eyes running through their design steps.

 

Reference design PDF is at https://www.ti.com/lit/ug/tiduc5...

 

In equation 25, page 17 - the required attenuation is calculated as 30.76 dB... but if I run that calculation, using all of their numbers - I get 51.56dB.

 

What do you guys get? Would like a second opinion before I go knocking on the door of TI support asking if there's a typo?

 

Many thanks in advance.

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Pay attention to whether you use degree or radians...both numbers are obtained.

 

duty 0 to 100%--->  0 to pi rads (180 deg) makes sense.

 

they should have used radians button, but apparently pushed deg...and got the wrong anwser

Contact them & ask for a banana cake reward

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

Last Edited: Fri. Jun 4, 2021 - 02:14 AM
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avrcandies wrote:

Pay attention to whether you use degree or radians...both numbers are obtained.

 

duty 0 to 100%--->  0 to pi rads (180 deg) makes sense.

 

they should have used radians button, but apparently pushed deg...and got the wrong anwser

Contact them & ask for a banana cake reward

 

Ah, of course - thank you.

 

What do you mean sorry by "they got the wrong answer". If I use radians, I get the same answer as in the TI ref design. Should those formulae not use radians?

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If I use radians, I get the same answer as in the TI ref design. Should those formulae not use radians?

They should have used radians angle and pushed radians (sin3.14159=1)

they used radians angle and pushed deg  (sin90=1)

 

They could have used D*180  (degrees angle)  and pushed deg (sin90=1)

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!