I am designing a battery charger (li Ion, series dual) using MCP73842
Max input voltage is 10.5V (Vdd)
Battery Specs
Minimum cutoff voltage is at 5.2V
Max cutoff voltage at 8.4V
Charge Current I am using is 1A (Minimum)
Worst Case Pd is when the changing shifts from Preconditioning to Constant Current
which is (10.5V - 5.2V) / 1A = 5.3Watts
The area that I max have for Mosfet is 1.5 or 2 x 1 Cms each layer (Its a 6 layer board)
Schematic I am using is
**broken link removed**
The Board File is
As you can see there hardly is any space.
The Max height I can have is 3mm. This area is below the PCB and will finally sit very close to ABS
More heat can melt that plastic.
Considering worst case wattage (5.3 to 5.5Watt) has to be handled by the MOSFET and I am not sure how to choose appropriate part or go ahead from here.