Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

  • Locked Locked
  • Replies 5 replies
  • Subscribers 40 subscribers
  • Views 2592 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

lack of esr in capacitor

user4762868
Prodigy 150 points
Other Parts Discussed in Thread: TINA-TI

         

     I can not enter the esr value of a capacitor. According to informations that I get from internet, I added a resistor as series with capacitor instead of esr value. For example; if esr value is 200m ohm, I added a resistor(200m ohm) as series with capacitor. Actually, my main purpose is measure output impedance. Therefore, I added an ohmmeter to circuit. My measurement results are wrong because of esr resistors. If I delete esr resistors, I can observe approximately true graph.I want to ask two question.

1)How I  enter esr value?

2)How I measure output impedance by using ohmmeter?

  • TI__Mastermind 41310 points

    Are you measuring impedance or simulating impedance? If you are measuring impedance, the construction of a capacitor REQUIRES that the capacitor has ESR. It is not an added component, it is part of the physical make up of the device.

    If you are simulating ESR, then you can simply add the resistor in series with the capacitor. In order to measure the impedance properly, you would have to measure across the entire model (both the capacitor and resistor as a whole).

    Could you show us what circuit you are using and how you are trying to measure it?

  • in reply to Britt Brooks - Online Design Tools
    Prodigy 150 points

    In this circuit C1 has 150m esr and C2 has 130m esr.When I double click on capacitor I can  enter properties of capacitor. But, these properties  don't include esr value. Therefore, I connected a 130m and a 150m resistor as series to capacitors instead of esr values.

        But,with this method I can not obtain correct graph. I want to make AC Analysis and  obtain gain phase graph. How I can enter ers values correctly?  

       As a second question I want mesure output impedance.I deleted voltage source from circuit and then I connected an ohmmeter to circuit.Then I made AC Analysis.I built this circuit:

     

       But, with this circuit I obtain wrong output impedance graph.But,if I delete esr resistors(130m and 150m). I can obtain correct correct output impedance graph. Can you explain me how I can measure output imdepance by using this circuit?.How ı can enter esr values?

         Thank you,

  • in reply to user4762868
    TI__Mastermind 41310 points

    It appears that you are using TINA-TI.

    Do you actually believe that the 150mOhm resistor is in series with the capacitor C1 in your circuit? From the point of view of the inductor, I'd agree, but from the Ohm meter, not so much (or from the VF1 output).

    Is R1 (the 838mOhm resistor) your load? Is it supposed to be in series with your capacitor? If so, I would use this schematic:

    Which gives the following AC response:

    Similarly, you could use the Ohm meter by removing VG1 and connecting the Ohm meter from the original VF1 point to Ground.

    BTW, you can add series resistance to the inductor with the RSer parameter in the device. To display the value chosen, simply click on the box next to the parameter value.

    I hope that this information helps.

  • in reply to Britt Brooks - Online Design Tools
    Prodigy 150 points

        This information was very helpful for me, thank you.Now, I have another problem.From this website   

     

    I want to download and simulate both tina ti and spice models of a driver.When I download tina ti model it works correctly,but I can not open spice model in LT Spice.Can you describe me how I can open a spice model that downloaded from this website in LT Spice?

  • in reply to user4762868
    TI__Mastermind 41310 points

    Unfortunatley, the EULA (End Users License Agreement) that you accepted when installing LTSpice prohibits other semiconductor vendors from using LTSpice for marketing of their IC's. We are not allowed to help any customer that is using LTSpice with our products.

    You can download the PSpice model to your machine and seek help from the LTSpice users forum for how to use a third party spice model in LTSpice.