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LMG3410R050: About further datasheet parameters

Damith Pavithra
Expert 1125 points
Part Number: LMG3410R050

Hello

Can i Please get the Ids on vs Temperature curve for LMG3410R050. Datasheet seems missed that vital information.
Aslo can you tell me how the normalized Rds on is calculated.
Aslo i note that Ids rating stated as 12A at 125C in the webpage while datasheet says its 34A at 25C.
Normally, Product descriptions like Drain current rating state ratings in normal temperatures like 25C. Is there any reason why TI stated it at the extreme 125C. 
Can i use this device in 30A applications safely. 

Best regards
Damith pavithra

  • 0
    TI__Intellectual 2945 points

    Hi Damith,

    The Ids and temperature relationships can be seen in Figure 3 of the data sheet. There is only data for 25 C and 125 C. 

    In regards to the current rating, the recommended Ids operating condition is 12 A. However, depending on the Vds, you should be able to operate this safely at 30 A, as shown below. 

    What is your intended Vds voltage?

    Best regards,

    John

  • 0 in reply to John Gomez
    Expert 1125 points

    Hello John

    Thank you for the reply.

    Vds voltage will be above 200V.  My question is why the Ids rating at 125C is given as recommended Ids. If the chip placed in a circuit with heat sinks with the capability of running on lower temperature like 60C or 70C, it should be able to handle more than 27A or something.
    So why 12A recommended. 

  • 0 in reply to Damith Pavithra
    TI__Intellectual 2945 points

    Hi Damith,

    If heat sinks are available to run the device at at that temperature, there should be no problem running at 27 A. Since testing on Ids was conducted at 125 C and 25 C, the recommended Ids current is given at 125 C because it is a more realistic operating temperature as opposed to 25 C. 

    Best regards,

    John

  • 0 in reply to John Gomez
    Expert 1125 points

    Hi John

    According to my understanding, 125C is pretty unrealistic for a good design.. Datasheet given Current at 100C which is 27A. That means they measured it at 100C also, right?. Therefore, your reason is not accurate, i think  .

    12A is less than half  of the Current in 100C (27A). Manufacturers always try to state their devices' maximum capabilities as recommended ratings. So 12A is very bad rating to be showed in product description pages, while 27A can flow in 100C. 100C is also kind of extreme even for a basic design with poor thermal handling capabilities.
    Therefore, i want to know the real reason, why that much derated (less than half of absolute maximum)  value is provided as recommended current. 

    Thank you
    Damith

  • 0 in reply to Damith Pavithra
    TI__Intellectual 2945 points

    Hi Damith, 

    You are correct - it is not realistic that a good design would be continuously operated at 125 C. However, the maximum recommended operating temperature is 125 C, and the corresponding recommended drain current of 12 A is provided. Thus, our parametric table on the product website shows the recommended drain current for the maximum Tj of 125 C. You are correct in mentioning that most manufacturers list the absolute ratings at lower operating temperatures - we are looking at updating the parametric table for all of our GaN products to include more significant operating parameters, as well as updated values at different operating temperatures. 

    Best regards,

    John

  • 0 in reply to Damith Pavithra
    TI__Intellectual 2945 points

    Hi Damith, 


    The current value of 27 A that you are providing - is that the RMS, average, or peak value of your expected waveform? Additionally, how much power is intended for this application? Please let us know in order to confirm compatibility with our parts. 

    Best regards,

    John 

  • 0 in reply to John Gomez
    Expert 1125 points

    Hi john

    Thank you for your valuable time.

    Still i am not confident about the 27A rating at 100C because product page description and datasheet emphasizes 12A.
    Its very strange to use half of the absolute maximum ratings.

    I stated 27A because it is in the datasheet.
    Our application is diode clamped three level inverter. Power rating is 6kW. DC bus voltage is 400V.  DC bus current would be 15A.  Mosfets have pulsed currents which have peaks near 27A.

    Thank you
    Damith

  • 0 in reply to Damith Pavithra
    TI__Intellectual 2945 points

    Hi Damith,

    We are checking this internally and will get back to you promptly. Thanks for your patience.

    Best regards,
    John

  • 0 in reply to John Gomez
    Expert 1125 points

    Hi john.

    Im looking forward to it.

    Thank you verymuch for your help.

    Best regards

    Damith

  • 0 in reply to Damith Pavithra
    TI__Intellectual 2945 points

    Hi Damith,

    Thank you for your patience. Below is some information regarding the current specs that are shown in our data sheet:

    12A at 125C: This is based on long-term reliability (electromigration) of the metallization distribution system.

    34A at 25C and 27A at 100C: these are the abs max ratings, which means that the package can handle these currents for a short while as long as the temperature is kept below 125C.

    There is also the SOA plot in Figure 12 of the datasheet. This represents the turn-on hard-switching current - IL+(C_oss+C_par)*dV/dt at peak current. For R050, we use140pF for the equivalent C_oss. If the peak switching current is lower than the SOA boundary, you can expect to enjoy reliable operation.

    Best regards,
    John

  • 0 in reply to John Gomez
    Expert 1125 points

    Hi John

    Thank you for your valuable time.
    I want to further clarify your answer. Sorry for any trouble which i might be causing. 
    Here is what i got from your answer. Please correct me if im wrong.

    1. These current values are rms values, not peak values

    2. So 12A is recommended for long term reliability. If we put 27A , even in low temperature, device long term reliability will be low.

    3. 27A can be applied at low temperature for a short time. Even with the low temperature like 60,70C it cannot be applied long term.

    Am i right?

    Best Regards
    Damith

  • 0 in reply to Damith Pavithra
    TI__Intellectual 2945 points

    Hi Damith,

    1. Yes, the current values provided in the data sheet are rms values, not peak values.

    2,3. The device will handle 27 amps reliably while operating with a junction temperature below 100 C. 

    The 27 and 34 A values that are shown in the data sheet are actually recommended ratings at their respective temperatures. We are looking to update these recommended values in the datasheet and in the product page to more accurately describe the operation of our part.  

    Best regards,

    John