2.2 Thermal Characteristics

The temperature variable in Microchip’s Designer software refers to the junction temperature, but not to the ambient temperature. This is an important distinction because dynamic and static power consumption cause the chip junction temperature to be higher than the ambient temperature. The following equation can be used to calculate junction temperature.

Where,

T_a = Ambient Temperature

ΔT = Temperature gradient between junction (silicon) and ambient

ΔT = θja × P

Where,

P = Power

θja = Junction to ambient of package.

θja numbers are located in Table 2-6