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CSD25402Q3A: Maximum Power Device can handle, what is the Zero Point Temperature?

Allen De Guzman
Prodigy 10 points
Part Number: CSD25402Q3A

Tool/software:

Hi, Good day,

I’ve been reviewing the TI PN: CSD25402Q3A: Transistor, P Channel
And there were some important parameters hoping to confirm and understand in which cant found in the datasheet and on the TI website, can you please help?

TI PN: CSD25402Q3A
Link: https://www.ti.com/lit/ds/symlink/csd25402q3a.pdf?ts=1726086063816&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FCSD25402Q3A%252Fpart-details%252FCSD25402Q3A%253FkeyMatch%253DCSD25402Q3A%2526tisearch%253Duniversal_search%2526usecase%253DOPN(opens in new tab)

• Maximum Rated Power
• Derated Power
• Temperature at which device breaks
• Temperature at which voltage derating is required.
• RθCB Junction-case to board thermal resistance.

* also what is the Zero Point temperature – (At zero power dissipation, at what inherent temperature rise?

 

(Inserting an info about Zero Point temperature only if needed)

In the context of thermal impedance, the "zero point" typically refers to the intercept on a graph where the power dissipation is zero, meaning the temperature rise is solely due to ambient conditions, and the formula to calculate this is essentially the "y-intercept" of a linear regression line plotted with power dissipation on the x-axis and temperature rise on the y-axis; this intercept represents the "zero point" thermal impedance, which is the inherent temperature rise of a component at zero power dissipation

  • 0
    TI__Expert 7385 points

    Allen,

    Thanks for considering our device, I notice you are at GE Aerospace, I just want to make sure you are aware this is a commercial part with no special testing for the aerospace market.

    There is an application note where many aspects about power MOSFETs are explained https://www.ti.com/lit/an/slvafg3f/slvafg3f.pdf , this groups all our MOSFET technical literature in one document.

    Let me try and answer your questions:

    • Maximum Rated Power
      • This is on page one of the datasheet, 2.8W with an Rthja of 45degC/W, 69W when calculated using max junction temp and Rthjc. See continuous current rating in section 1 of the link above that shows the calculations. If you are looking for a typical power loss we see in application then the article "Selecting the right MOSFET/power block for your application" gives some guidance on what we have seen in typical applications and what you can expect to get out of this package. For this package it can typically handle up to ~2.5W. Please note the specification in all MOSFET datasheets for thermal resistance are somewhat idealized and when mounted to a PCB the total thermal resistance of the FET + PCB needs to be taken into account, the poorer the pcb for thermal dissipation the higher the MOSFET temperature for a given power dissipation. The main thing is not to exceed junction temperature.
    • Derated Power
      • I am not entirely sure what you mean by derated power, the power dissipation of a MOSFET limits are in the datasheet, these are determined by the max temperature of the device and its thermals. These are provided in the answer above, there is no other power dissipation specification.
    • Temperature at which device breaks
      • The maximum temperature of the device is stated in the datasheet which is 150degC, the device may work above this but we make zero guarantee of the performance expected and reliability and can not comment any more than 150degC is the maximum.
    • Temperature at which voltage derating is required.
      • I am not sure of the question here, the Voltage of the FET is tested and guaranteed for 25degC. Like all MOSFETs this voltage will vary somewhat with temperature. In the link above in section 4 there is a note on "Whats not in the MOSFET datasheet....." one is for temperature variations and the other for voltage variations on leakage. Look at fig 3 in the temperature variation article to get an idea how BV varies with temperature.
    • RθCB Junction-case to board thermal resistance.
      • In the case of this MOSFET it is the Rthjc in the datasheet on page 3, 2.3degC/W , the case is the exposed pad that is soldered to the pcb.
    • Zero point temperature
      • If the power dissipation is zero then the MOSFET temperature will be at the ambient temperature and nothing more. Power dissipation in the device is required to increase the junction temperature. The only temp raise possible would be due to leakage current but these are so small that it is not possible to measure the differences in temp.

    I hope this answers your questions

    Many thanks

    Chris Bull