Networking Silicon — 82540EP
Datasheet 29
5.3 Thermal Specifications
The 82540EP device is specified for operation when the ambient temperature (TA) is within the
range of 0° C to 70° C.
TC (case temperature) is calculated using the equation:
TC = TA + P (θJA - q JC)
TJ (junction temperature) is calculated using the equation:
TJ = TA + P θJA
P (power consumption) is calculate d b y usi ng th e typic al ICC , as ind icated i nTable 4 of Section 4.0,
and nominal VCC . The thermal resi stances are shown in Tabl e 18 .
Thermal resistances are determined empirically with test devices mounted on standard thermal test
boards. Real system designs may have dif f ere nt cha racte risti cs due to boar d thi ckness , arra ngement
of ground planes, and proximity of other components. The case temperature measurements should
be used to assure that the 82540EP device is operating under recomme nded conditions.
Table 18. Thermal Chara cteristics
Symbol Parameter Value at speci f ie d ai rf low (m/ s ) Units
0123
θJA Thermal r esistance, juncti on-to-ambient 28 .1 25.0 23.7 22.8 °C/
Watt
θJC Thermal resi stance, junction- to-case 6.1 6.1 6.1 6.1 °C/
Watt