Digital Equipment AXPpci 33, Руководство по конструкции

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3 Environmental Data
This chapter gives environmental data for:
• Cooling requirements
• DC power inputs
• Electrostatic discharge (ESD) considerations
• Telecommunication regulatory standards
• Electromagnetic compatibility (EMC) considerations
• Reliability data
3.1 Cooling Requirements
Maintaining proper component case or junction temperatures is important
in maintaining system reliability.
3.1.1 Air Flow
Air-flow direction relative to the core module set must be parallel to
the SIMMs, the DECchip 21066 heatsink fins, and the PCI/ISA option
modules. Air-flow velocity must be sufficient to maintain component case
temperatures below their maximum rating. A guideline for maximum case
temperatures, excluding the DECchip 21066, is 75°C (167°F) for metal
oxide semiconductor (MOS) devices and 100°C (212°F) for bipolar devices.
Table 3–1 lists the DECchip 21066 maximum case temperature limits.
Table 3–1 DECchip 21066 Maximum Case Temperature Limits
Alpha Processor Maximum Case Temperature
DECchip 21066–166 85°C (185°F)
DECchip 21066A–233 84°C (183°F)
DECchip 21068–66 93°C (199°F)
DECchip 21068A–100 93°C (199°F)
3.1.2 DECchip 21066 Heatsink Selection
The DECchip 21066 requires a heatsink, thermal interface pad, and
sufficient air flow to keep it below its maximum case temperature. Tables
3–2 through 3–7 include various tested and recommended heatsink and
airflow combinations. Appendix A lists suppliers and associated part
numbers.
3–1