I need 3A @ 5V so 15W. The total current is 6A which is fine, and it can operate at 5V, but doesn't mean I'm going to get that much out of it in reality. I don't see in the datasheet where the max power consumption is indicated.
I see some thermal indications celcius per watt, but it's hard to know what that will be until it's physically tested.
Is there some information on total power consumption for the chip I'm not seeing?
Luc,
For the TPS22958, the package is going to make a difference on how much current/power the device can dissipate. You can see the ratings in the datasheet:
Since very little voltage is dropped over the FET, the actual voltage on the input doesn't factor in too much., These all depend on the thermals/layout, however the main variable here is on-resistance and how hot the integrated FET gets. To calculate this, you use the following formula:
For RON- we spec this in the datasheet at:
At 5V and 3A, assuming the worst case on-resistance/ambient temperature of 24mOhm the junction temperature would be (approximately) 119C, which is above the part's maximum operation temperature of 105C. This particular load switch doesn't have any thermal shutdown protections so the device will likely still work/power, however reliability would not be guaranteed. Depending on your ambient temperature this could decrease, however I would recommend a new device such as the TPS22992 with a lower on resistance.
Best Regards,
Tim
