Question about Tantalum Film Resistor in ADS

Hello everyone,
I want to simulate some tantalum film resistors in ADS.I will take the Libra thin film resistor model
from ADS Library. I know the thickness and resistivity of Tantalum,so I can easily find the sheet resistance.I will put the 50 ohm value of sheet resistance there. Than I will change the length and width of TFR modelto get my desire resistance value.My question is am I right to do so? Thanks in advance.

kamranraja222 said:

I will put the 50 ohm value of sheet resistance there. Than I will change the length and width of TFR modelto get my desire resistance value.My question is am I right to do so?

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It is better (more realistic) to use the actual physical size, and adjust the sheet resistance value.

volker@muehlhaus said:

It is better (more realistic) to use the actual physical size, and adjust the sheet resistance value.

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I think I am not getting your point. Can you please explain little more.Thanks

Maybe I misunderstood your project, but I would use the correct sheet resistance (same as in hardware) instead of using 50 Ohm.

volker@muehlhaus said:

Maybe I misunderstood your project, but I would use the correct sheet resistance (same as in hardware) instead of using 50 Ohm.

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As far as my knowledge, sheet resistance depend on resistivity and thickness of the material.than you can use length and width to get the desired actual value. Am I right? My second question is that when we are using film resistor in ADS, How can we set the resistor material?

kamranraja222 said:

As far as my knowledge, sheet resistance depend on resistivity and thickness of the material.

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Correct. Material is Tantalum in your case and thickness is usually given (fixed) by the manufacturing process. This means that sheet resistance will be different from 50 Ohm in many cases. No problem, you just need to set the actual sheet resistance value in your model.

kamranraja222 said:

My second question is that when we are using film resistor in ADS, How can we set the resistor material?

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You don't need to define/set the material. Just provide the correct sheet resistance (calculated from conductivity and thickness).