TPS25940: max. power dissipation

Hi Brian,

Thanks for reaching out to us!

1. Package type is 20 pin  WQFN

2. We don't have a spec like max power dissipation. Device has a thermal shutdown feature. During stress events such as overcurrent or short at output when power dissipation across device increases then the junction temperature of IC also increases. When this junction temperature crosses the thermal shutdown threshold the device turns off.  

Regards

Kunal Goel

In the other device, there is a specified max. power dissipation.

Is it possible to calculate since my customer would like to get this parameter to do the thermal simulation. Thanks. 

Regards

Brian W

Hi Brian,

As I mentioned that device has thermal shutdown protection. So we can estimate max power dissipation before device hits thermal shutdown like this:

1. Tj(junction temperature)=Ta(ambient temperature)+[Pd(Power dissipation)*RθJA(Junction-to-ambient thermal resistance)]

2. When Tj=160C device hits thermal shutdown

3. So putting Tj<160C will give max power dissipation allowed to prevent thermal shutdown.

4. Pd(max)=(160-TA)/RθJA ,RθJA=38.1

Also during normal device operation when there is no overcurrent(current<current limit) then max power dissipation=(RON*Max operating current)

Regards

Kunal Goel