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Intel 521 Data Sheet - Page 95

Variable Speed Fan

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Boxed Processor Specifications 7.3.2 Variable Speed Fan If the boxed processor fan heatsink 4-pin connector is connected to a 3-pin motherboard header it will operate as follows: The boxed processor fan will operate at different speeds over a short range of internal chassis temperatures. This allows the processor fan to operate at a lower speed and noise level, while internal chassis temperatures are low. If internal chassis temperature increases beyond a lower set point, the fan speed will rise linearly with the internal temperature until the higher set point is reached. At that point, the fan speed is at its maximum. As fan speed increases, so does fan noise levels. Systems should be designed to provide adequate air around the boxed processor fan heatsink that remains cooler then lower set point. These set points, represented in Figure 7-9 and Table 7-2, can vary by a few degrees from fan heatsink to fan heatsink. The internal chassis temperature should be kept below 38 ºC. Meeting the processor's temperature specification (see Chapter 5) is the responsibility of the system integrator. The motherboard must supply a constant +12 V to the processor's power header to ensure proper operation of the variable speed fan for the boxed processor. Refer to Table 7-1 for the specific requirements. Figure 7-9. Boxed Processor Fan Heatsink Set Points Increasing Fan Speed & Noise Higher Set Point Highest Noise Level Lower Set Point Lowest Noise Level X Y Z Internal Chassis Temperature (Degrees C) Datasheet 95

Section	Page
Contents	3
Revision History	7
Intel® Pentium® 4 Processors 570/571, 560/561, 550/551, 540/541, 530/531, and 520/521	9
1 Introduction	11
1.1 Terminology	12
1.1.1 Processor Packaging Terminology	12
1.2 References	13
2 Electrical Specifications	15
2.1 FSB and GTLREF	15
2.2 Power and Ground Lands	15
2.3 Decoupling Guidelines	15
2.3.1 VCC Decoupling	16
2.3.2 FSB GTL+ Decoupling	16
2.3.3 FSB Clock (BCLK[1:0]) and Processor Clocking	16
2.4 Voltage Identification	17
2.4.1 Phase Lock Loop (PLL) Power and Filter	19
2.5 Reserved, Unused, FC and TESTHI Signals	20
2.6 FSB Signal Groups	21
2.7 GTL+ Asynchronous Signals	22
2.8 Test Access Port (TAP) Connection	23
2.9 FSB Frequency Select Signals (BSEL[2:0])	23
2.10 Absolute Maximum and Minimum Ratings	24
2.11 Processor DC Specifications	24
2.12 VCC Overshoot Specification	33
2.12.1 Die Voltage Validation	33
2.13 GTL+ FSB Specifications	34
3 Package Mechanical Specifications	35
3.1 Package Mechanical Drawing	35
3.2 Processor Component Keep-Out Zones	39
3.3 Package Loading Specifications	39
3.4 Package Handling Guidelines	39
3.5 Package Insertion Specifications	40
3.6 Processor Mass Specification	40
3.7 Processor Materials	40
3.8 Processor Markings	40
3.9 Processor Land Coordinates	41
4 Land Listing and Signal Descriptions	43
4.1 Processor Land Assignments	43
4.2 Alphabetical Signals Reference	66
5 Thermal Specifications and Design Considerations	75
5.1 Processor Thermal Specifications	75
5.1.1 Thermal Specifications	75
5.1.2 Thermal Metrology	79
5.2 Processor Thermal Features	79
5.2.1 Thermal Monitor	79
5.2.2 Thermal Monitor 2	80
5.2.3 On-Demand Mode	81
5.2.4 PROCHOT# Signal	82
5.2.5 THERMTRIP# Signal	82
5.2.6 TCONTROL and Fan Speed Reduction	82
5.2.7 Thermal Diode	83
6 Features	85
6.1 Power-On Configuration Options	85
6.2 Clock Control and Low Power States	85
6.2.1 Normal State	86
6.2.2 HALT and Enhanced HALT Powerdown States	86
6.2.2.1 HALT Powerdown State	86
6.2.2.2 Enhanced HALT Powerdown State	86
6.2.3 Stop-Grant State	87
6.2.4 Enhanced HALT Snoop or HALT Snoop State, Grant Snoop State	88
6.2.4.1 HALT Snoop State, Grant Snoop State	88
6.2.4.2 Enhanced HALT Snoop State	88
7 Boxed Processor Specifications	89
7.1 Mechanical Specifications	90
7.1.1 Boxed Processor Cooling Solution Dimensions	90
7.1.2 Boxed Processor Fan Heatsink Weight	91
7.1.3 Boxed Processor Retention Mechanism and Heatsink Attach Clip Assembly	91
7.2 Electrical Requirements	91
7.2.1 Fan Heatsink Power Supply	91
7.3 Thermal Specifications	93
7.3.1 Boxed Processor Cooling Requirements	93

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Datasheet

Boxed Processor Specifications

7.3.2

Variable Speed Fan

If the boxed processor fan heatsink 4-pin connector is connected to a 3-pin motherboard header it

will operate as follows:

The boxed processor fan will operate at different speeds over a short range of internal chassis

temperatures. This allows the processor fan to operate at a lower speed and noise level, while

internal chassis temperatures are low. If internal chassis temperature increases beyond a lower

set point, the fan speed will rise linearly with the internal temperature until the higher set point

is reached. At that point, the fan speed is at its maximum. As fan speed increases, so does fan

noise levels. Systems should be designed to provide adequate air around the boxed processor

fan heatsink that remains cooler then lower set point. These set points, represented in

Figure 7-9

and

Table 7-2

, can vary by a few degrees from fan heatsink to fan heatsink. The

internal chassis temperature should be kept below 38 ºC. Meeting the processor's temperature

specification (see

Chapter 5

) is the responsibility of the system integrator.

The motherboard must supply a constant +12 V to the processor's power header to ensure proper

operation of the variable speed fan for the boxed processor. Refer to

Table 7-1

for the specific

requirements.

Figure 7-9. Boxed Processor Fan Heatsink Set Points

Lower Set Point

Lowest Noise Level

Internal Chassis Temperature (Degrees C)

Increasing Fan

Speed & Noise

Higher Set Point

Highest Noise Level