AMD Athlon 27493 - Manual (Page 52)

40 Electrical Data Chapter 8
AMD Athlon™ XP Processor Model 10 Data Sheet 26237C—May 2003
Preliminary Information
Thermal limits in motherboard design are necessary to protect
the processor from thermal damage. T
S H U T D OW N
is the
temperature for thermal protection circuitry to initiate
shutdown of the processor. T
SD_DELAY
is the maximum time
allowed from the detection of the over-temperature condition to
processor shutdown to prevent thermal damage to the
processor.
Systems that do not implement thermal protection circuitry or
that do not react within the time specified by T
SD_DELAY
can
cause thermal damage to the processor during the unlikely
events of fan failure or powering up the processor without a
heat-sink. The processor relies on thermal circuitry on the
motherboard to turn off the regulated core voltage to the
processor in response to a thermal shutdown event.
Thermal protection circuitry reference designs and thermal
solution guidelines are found in the following documents:
■
AMD Athlon™ Processor-Based Motherboard Design Guide,
order# 24363
■ AMD Thermal, Mechanical, and Chassis Cooling Design Guide,
order# 23794
See http://www.amd.com for more information about thermal
solutions.
Table 18 shows the T
SHUTDOWN
and T
SD_DELAY
specifications
for circuitry in motherboard design necessary for thermal
protection of the processor.
Table 18. Guidelines for Platform Thermal Protection of the Processor
Symbol Parameter Description Max Units Notes
T
SHUTDOWN
Thermal diode shutdown temperature for processor protection 125
°C
1, 2, 3
T
SD_DELAY
Maximum allowed time from T
SHUTDOWN
detection to processor shutdown 500 ms 1, 3
Notes:
1. The thermal diode is not 100% tested, it is specified by design and limited characterization.
2. The thermal diode is capable of responding to thermal events of 40°C/s or faster.
3. The AMD Athlon™ XP processor model 10 provides a thermal diode for measuring die temperature of the processor. The
processor relies on thermal circuitry on the motherboard to turn off the regulated core voltage to the processor in response to a
thermal shutdown event. Refer to AMD Athlon™ Processor-Based Motherboard Design Guide, order# 24363, for thermal
protection circuitry designs.