Hi there !
I would need use the LM338 TO-220 with 2A.
Specs.
Rthja= 50 C/W
Rth jc= 4 C/W
Requirements:
Tj=100 degC - Ta= 50 Deg C
Pawer supply ; 12 v @1.5 A
Calculation:
PD= (12 V - 5 V) x 2 A= 14 W
Heatsink thermal Resistance
Rthsa= (Tj-Ta) / PD - RthJc- Rthcs = (100-50) C/ 14W - 4C/w-0.1C/W= -1.43C/W
Which is the meaning of negative Rthsa ???
Thanks fore any help.
I would need use the LM338 TO-220 with 2A.
Specs.
Rthja= 50 C/W
Rth jc= 4 C/W
Requirements:
Tj=100 degC - Ta= 50 Deg C
Pawer supply ; 12 v @1.5 A
Calculation:
PD= (12 V - 5 V) x 2 A= 14 W
Heatsink thermal Resistance
Rthsa= (Tj-Ta) / PD - RthJc- Rthcs = (100-50) C/ 14W - 4C/w-0.1C/W= -1.43C/W
Which is the meaning of negative Rthsa ???
Thanks fore any help.