RM7965A-900UI 900 MHz 64-bit Microprocessor Data Sheet
16 Thermal Information
This product is designed to operate over a wide temperature range when used with a heat sink
and is suited for commercial applications such as central office equipment.
Maximum long-term operating junction temperature (TJ) to ensure adequate
long-term life.
88°C
Minimum ambient temperature (TA)
0°C
Table 31 Device Compact Model2
Ambient
900 MHz
SA
0.27
6.52
13.23
Junction-to-Case Thermal Resistance, JC
Junction-to-Board Thermal Resistance, JB
JA (°C/W) (without heat sink)
Heat Sink
CS
Table 32 Heat Sink Requirements
Device
Compact
Model
Case
4
SA+CS
The sum of SA + CS must be less than or equal to:
[(105 - TA) / PD ] - JC ] °C/W
JC
where:
Junction
JB
TA is the ambient temperature at the heat sink
location
PD is the operating power dissipated in the package5
Board
SA and CS are required for long-term operation
Notes:
1. The minimum ambient temperature requirement for Central Office Equipment approximates the
minimum ambient temperature requirement for Commercial Equipment.
2. Short-term is used as defined in Telcordia Technologies Generic Requirements GR-63-Core; for more
information about the GR-63-CORE standard, see Telcordia Technologies. Network Equipment-
Building System (NEBS) Requirements: Physical Protection: Telcordia Technologies Generic
Requirements GR-63-CORE. Issue 1. October 1995.
3. JC, the junction-to-case thermal resistance, is a measured nominal value plus two sigma. JB, the
junction-to-board thermal resistance, is obtained by simulating conditions described in JEDEC
Standard JESD 51-8; for more information about the JESD51-8 standard, see Electronic Industries
Alliance 1999. Integrated Circuit Thermal Test Method Environmental Conditions -Junction-to-Board:
JESD51-8. October 1999.
4.
SA is the thermal resistance of the heat sink to ambient. CS is the thermal resistance of the heat sink
attached material. The maximum SA required for the airspeed at the location of the device in the
system with all components in place.
5. Power depends upon the operating mode. To obtain power information, refer to the column under
thermal in Table 29.
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2100294, Issue 2
67
PMC [ PMC-SIERRA, INC ]
