Intel BX80570E8400 Mechanical Design Guidelines - Page 32

Thermal Management Logic and Thermal Monitor Feature

32

Thermal and Mechanical Design Guidelines

4.2.1

PROCHOT# Signal

The primary function of the PROCHOT# signal is to provide an external indication that

the processor has reached the TCC activation temperature. While PROCHOT# is

asserted, the TCC will be activated. Assertion of the PROCHOT# signal is independent

of any register settings within the processor. It is asserted any time the processor die

temperature reaches the trip point.

PROCHOT# can be configured using BIOS as an output or bi-directional signal. As an

output, PROCHOT# will go active when the processor temperature of either core

reaches the TCC activation temperature. As an input, assertion of PROCHOT# will

activate the TCC for both cores. The TCC will remain active until the system de-asserts

PROCHOT#

The temperature at which the PROCHOT# signal goes active is individually calibrated

during manufacturing. Once configured, the processor temperature at which the

PROCHOT# signal is asserted is not re-configurable.

One application of the Bi-directional PROCHOT# is for the thermal protection of

voltage regulators (VR). System designers can implement a circuit to monitor the VR

temperature and activate the TCC when the temperature limit of the VR is reached. By

asserting PROCHOT# (pulled-low) which activates the TCC, the VR can cool down as a

result of reduced processor power consumption. Bi-directional PROCHOT# can allow

VR thermal designs to target maximum sustained current instead of maximum

current. Systems should still provide proper cooling for the VR, and rely on bi-

directional PROCHOT# signal only as a backup in case of system cooling failure.

Note:

A thermal solution designed to meet the thermal profile specifications should rarely

experience activation of the TCC as indicated by the PROCHOT# signal going active.

4.2.2

Thermal Control Circuit

The Thermal Control Circuit portion of the Thermal Monitor must be enabled for the

processor to operate within specifications. The Thermal Monitor’s TCC, when active,

will attempt to lower the processor temperature by reducing the processor power

consumption. There are two methods by which TCC can reduce processor power

dissipation. These methods are referred to as Thermal Monitor 1 (TM1) and Thermal

Monitor 2 (TM2).

4.2.2.1

Thermal Monitor

In the original implementation of thermal monitor this is done by changing the duty

cycle of the internal processor clocks, resulting in a lower effective frequency. When

active, the TCC turns the processor clocks off and then back on with a predetermined

duty cycle. The duty cycle is processor specific, and is fixed for a particular processor.

The maximum time period the clocks are disabled is ~3

µ

s. This time period is

frequency dependent and higher frequency processors will disable the internal clocks

for a shorter time period. Figure 4-1 illustrates the relationship between the internal

processor clocks and PROCHOT#.

Performance counter registers, status bits in model specific registers (MSRs), and the

PROCHOT# output pin are available to monitor the Thermal Monitor behavior.

Section	Page
1 Introduction	9
1.1 Document Goals and Scope	9
1.1.1 Importance of Thermal Management	9
1.1.2 Document Goals	9
1.1.3 Document Scope	10
1.2 References	11
1.3 Definition of Terms	11
2 Processor Thermal/Mechanical Information	13
2.1 Mechanical Requirements	13
2.1.1 Processor Package	13
2.1.2 Heatsink Attach	15
2.1.2.1 General Guidelines	15
2.1.2.2 Heatsink Clip Load Requirement	15
2.1.2.3 Additional Guidelines	16
2.2 Thermal Requirements	16
2.2.1 Processor Case Temperature	16
2.2.2 Thermal Profile	17
2.2.3 Thermal Solution Design Requirements	17
2.2.4 TCONTROL	18
2.3 Heatsink Design Considerations	19
2.3.1 Heatsink Size	20
2.3.2 Heatsink Mass	20
2.3.3 Package IHS Flatness	21
2.3.4 Thermal Interface Material	21
2.4 System Thermal Solution Considerations	22
2.4.1 Chassis Thermal Design Capabilities	22
2.4.2 Improving Chassis Thermal Performance	22
2.4.3 Summary	23
2.5 System Integration Considerations	23
3 Thermal Metrology	25
3.1 Characterizing Cooling Performance Requirements	25
3.1.1 Example	26
3.2 Processor Thermal Solution Performance Assessment	27
3.3 Local Ambient Temperature Measurement Guidelines	27
3.4 Processor Case Temperature Measurement Guidelines	30
4 Thermal Management Logic and Thermal Monitor Feature	31
4.1 Processor Power Dissipation	31
4.2 Thermal Monitor Implementation	31
4.2.1 PROCHOT# Signal	32
4.2.2 Thermal Control Circuit	32
4.2.2.1 Thermal Monitor	32
4.2.3 Thermal Monitor 2	33
4.2.4 Operation and Configuration	34
4.2.5 On-Demand Mode	35
4.2.6 System Considerations	35
4.2.7 Operating System and Application Software Considerations	36
4.2.8 THERMTRIP# Signal	36
4.2.9 Cooling System Failure Warning	36
4.2.10 Digital Thermal Sensor	37
4.2.11 Platform Environmental Control Interface (PECI)	38
5 Balanced Technology Extended (BTX) Thermal/Mechanical Design Information	39
5.1 Overview of the BTX Reference Design	39
5.1.1 Target Heatsink Performance	39
5.1.2 Acoustics	40
5.1.3 Effective Fan Curve	41
5.1.4 Voltage Regulator Thermal Management	42
5.1.5 Altitude	43
5.1.6 Reference Heatsink Thermal Validation	43
5.2 Environmental Reliability Testing	43
5.2.1 Structural Reliability Testing	43
5.2.1.1 Random Vibration Test Procedure	43
5.2.1.2 Shock Test Procedure	44
5.2.2 Power Cycling	45
5.2.3 Recommended BIOS/CPU/Memory Test Procedures	46
5.3 Material and Recycling Requirements	46
5.4 Safety Requirements	47
5.5 Geometric Envelope for Intel® Reference BTX Thermal Module Assembly	47
5.6 Preload and TMA Stiffness	48
5.6.1 Structural Design Strategy	48
5.6.2 TMA Preload verse Stiffness	48
6 ATX Thermal/Mechanical Design Information	51
6.1 ATX Reference Design Requirements	51
6.2 Validation Results for Reference Design	53
6.2.1 Heatsink Performance	53
6.2.2 Acoustics	54
6.2.3 Altitude	54
6.2.4 Heatsink Thermal Validation	55
6.3 Environmental Reliability Testing	55
6.3.1 Structural Reliability Testing	55
6.3.1.1 Random Vibration Test Procedure	55
6.3.1.2 Shock Test Procedure	56
6.3.2 Power Cycling	57
6.3.3 Recommended BIOS/CPU/Memory Test Procedures	58
6.4 Material and Recycling Requirements	58
6.5 Safety Requirements	59
6.6 Geometric Envelope for Intel® Reference ATX Thermal Mechanical Design	59
6.7 Reference Attach Mechanism	60
6.7.1 Structural Design Strategy	60
6.7.2 Mechanical Interface to the Reference Attach Mechanism	61
7 Intel® Quiet System Technology (Intel® QST)	63
7.1 Intel® QST Algorithm	63
7.1.1 Output Weighting Matrix	64
7.1.2 Proportional-Integral-Derivative (PID)	64
7.2 Board and System Implementation of Intel® QST	66
7.3 Intel® QST Configuration and Tuning	68

Intel BX80570E8400 Mechanical Design Guidelines - Page 32

PROCHOT# Signal, Thermal Control Circuit

Page 32 highlights