• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 123 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.

TPS7B69-Q1: Junction thermal test

Imelda Zhang
Expert 3375 points
Part Number: TPS7B69-Q1

Hi Expert,

Thanks a lot for your warm help.

We all konw thermal is a pretty important parameter to LDO.

Here are 2 questions about actual test raised from me.

1. Should we use the thermocouple close to test the chip pin or top to capture the TA?

2. If we need to test the temperature on the top (pin), wha's the relationship between the temperature on pin(top) and RθJA/B/C, ψJT/B?

Thanks a lot for your kind help!

Kind Regards

Imelda

  • +1
    TI__Genius 12511 points

    Hi Imelda,

    1 To measure TA(Ambient temperature surrounding chip) you would place the thermocouple near the device, but making no contact with the case, board, or device in any way the measurement is for the air temperature surrounding the device. Placing the thermocouple floating 5-25mm away from the LDO would be sufficient to measure the quantity.

    2 Measuring the top of the case is what the RθJC and the ψJT parameters are for. Both of those are defined by the junction to top of case thermal resistance, and thermal impedance characterization parameter.

    2b If you are talking about the temperature of an actual pin on the device, there is no relationship between these quantities, instead you should place the thermocouple on the PCB near the device 5mm and use the for the B or board parameters

    Regards,

    John