I960 Datasheet, PDF (38/70 Pages) Intel Corporation – i960 RP/RD I/O PROCESSOR AT 3.3 VOLTS

i960^® Rx I/O Processor at 3.3 V
3.2.2 Thermal Analysis
This thermal analysis is based on the following
assumptions:
• Power dissipation is a constant 5 W.
• Maximum case temperature is 95° C.
Table 14 lists the case-to-ambient thermal resis-
tances of the 80960RP for different air flow rates
with and without a heat sink.
To calculate T_A, the maximum ambient temperature
to conform to a particular case temperature:
T_A = T_C - P (θ_CA)
Compute P by multiplying I_CC and V_CC. Valuesfor
θ_JC and θ_CA are given in Table 14.
Junction temperature (T_J) is commonly used in
reliability calculations. T_J can be calculated from θ_JC
(thermal resistance from junction to case) using the
following equation:
T_J = T_C + P (θ_JC)
Similarly, when T_A is known, the corresponding case
temperature (T_C) can be calculated as follows:
T_C = T_A + P (θ_CA)
The θ_JA (Junction to Ambient) for this package is
currently estimated at 9.74° C/Watt with no airflow.
θ_JA = θ_JC + θ_CA
Table 14. 352-Lead HL-PBGA Package Thermal Characteristics
Parameter
θ_JC (Junction-to-Case)
θ_CA (Case-to-Ambient)
Without Heatsink
θ_{WCiAth(CHaesaets-itnok-A2} mbient)
Thermal Resistance — °C/Watt
Airflow — ft./min (m/sec)
0
50
100
200
300
400
(0)
(0.25) (0.50) (1.01) (1.52) (2.03)
0.60
0.60
0.60
0.60
0.60
0.60
9.14
7.64
6.58
6.11
5.79
5.61
600
(3.04)
0.60
5.49
7.31
6.00
5.21
4.80
4.52
4.37
4.26
800
(4.06)
0.60
5.47
4.23
θ_JA
θ_JC
θ_CA
NOTES:
1. This table applies to a HL-PBGA device soldered directly onto a board.
2. See Table 15 for heatsink information.
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