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TPS22990: junction to case calculation

Roger Lin

Expert 3250 points

Part Number: TPS22990

Tool/software:

1. Please provide TPS22990DMLR power consumption at Vin = Vout = 0.8V, Vbias = 3.3V, ring temperature of 50 degrees Celsius.
Is it an on-line simulation or is there an Excel data sheet available?

2. Since the calculation provided by datasheet is the ambient temperature of the IC, they want to attach the thermal couple to the TOP case, do you have the junction to case calculation formula?

Thanks

0 Amrit Jit 4 months ago

TI__Mastermind 31841 points

Hello Roger,

power dissipation in load switch is mostly power dissipation through FET which is Id^2 * RDSon.

What's the load current and ambient temp for the application?

To calculate Tj(Junction temperature) you need to use the equation Tj = Ta + ( RθJA * PD ).

Ta = Ambient temperature

RθJA = Junction to ambient thermal resistance (51.4 °C/W)

PD= Id^2 * RDSon.

Thanks

Amrit

0 Roger Lin 4 months ago in reply to Amrit Jit

TI__Expert 3250 points

Hi Amrit,

Thanks for your reply, but the customer needs calculate the junction to case temperature

0 Amrit Jit 4 months ago in reply to Roger Lin

TI__Mastermind 31841 points

Hello Roger,

For junction to case, you can consider RθJC (65 degC/W) instead of RθJA in above mentioned equation.