AP-914 APPLICATION Order Number: 245098-001 Information this

The Datasheet Archive - 100 Million Datasheets from 7500 Manufacturers.

AP-914 APPLICATION Order Number: 245098-001 Information this

Datasheet Thumbnail

Top Searches for this datasheet

Pentium® XeonProcessor SMBus Thermal Reference
AP-914 APPLICATION
Order Number: 245098-001
Information this document provided connection with Intel products. license, express implied, estoppel otherwise, intellectual property rights granted this document. Except provided Intel's Terms Conditions Sale such products, Intel assumes liability whatsoever, Intel disclaims express implied warranty, relating sale and/or Intel products including liability warranties relating fitness particular purpose, merchantability, infringement patent, copyright other intellectual property right. Intel products intended medical, life saving, life sustaining applications. Intel make changes specifications product descriptions time, without notice. Designers must rely absence characteristics features instructions marked "reserved" "undefined." Intel reserves these future definition shall have responsibility whatsoever conflicts incompatibilities arising from future changes them. Pentium® Xeonprocessor contain design defects errors known errata which cause product deviate from published specifications. Current characterized errata available request. Contact your local Intel sales office your distributor obtain latest specifications before placing your product order. Copies documents which have ordering number referenced this document, other Intel literature, obtained calling 1-800-548-4725 visiting Intel's website http://www.intel.com Copyright Intel Corporation 1999. Third-party brands names property their respective owners.
AP-914
CONTENTS
PAGE PAGE 3.4. Filtering Thermal Sensor Readings.8 3.4.1. STATISTICAL ANALYSIS 3.4.2. CONTROL THEORY 3.4.3. RESPONSE TIME INITIATE SHUTDOWN.8 4.0. PROCESSOR CORE THERMAL DIODE.8 4.1. Ideality Factor.8 4.2. Thermal Diode Thermal Plate Measurements.9 5.0. CONCLUSION.10
0.INTRODUCTION. 1.1. Definition Terms 2.0. THERMAL SENSOR 3.0. THERMAL REFERENCE BYTE. 3.1. Using Scratch EEPROM Thermal Management 3.2. Calibration 3.2.1. PROCESSOR LEVEL 3.2.2. SYSTEM LEVEL. 3.3. Application Examples. 3.3.1. STANDARD OPERATION 3.3.2. CUSTOMIZED THRESHOLD BYTES SYSTEM COOLING DEPENDENCE 3.3.3. SYSTEM MANAGEMENT SOFTWARE 3.3.4. SMBALERT# EARLY DETECTION MECHANISM
FIGURES Figure Pentium® XeonProcessor Thermal Sensor Logical Schematic Figure Pentium® XeonThermal Plate Core Temperature Profiles
1.0. INTRODUCTION
Pentium® Xeonprocessor housed Single Edge Contact (S.E.C.) cartridge. Intel included thermal sensor inside Pentium Xeon processor thermal management server workstation systems. This feature allows flexibility precision thermal management applications. thermal sensor connected thermal diode processor core. core most significant source power dissipation cartridge. thermal diode temperature changes very closely with junction temperature. Thus, thermal sensor provides earliest indication thermal variation onset potential thermal solution failure. Note that maximum thermal plate specification remains governing condition guaranteed operation processor. some applications cache forcing function thermal plate temperature core being exercised high power mode. thermal diode located processor core does monitor cache temperature.
AP-914
basic thermal sensor described Pentium® XeonProcessor datasheet. thermal sensor provided deliver thermal data system with which system management software forecast onset potentially catastrophic event gracefully shut down take other reactive measures order preserve data integrity. calibration required effectively apply this technology. desired, custom threshold values determined individual operating conditions. Example applications discussed this document. Additionally, statistical methods discussed effective filtering thermal byte readings. Filtering ensures that isolated harmless transient changes temperature construed catastrophic conditions. This document describes thermal reference feature more detail, includes suggestions procedures more effective Pentium Xeon processor Thermal Reference Byte thermal sensor thermal management applications. Figure schematic representation components relative thermal reference feature.
CESSO INFO ATIO
SENS THERM ALDIO
Figure Pentium® XeonProcessor Thermal Sensor Logical Schematic
AP-914
Definition Terms
obtained using SMBus read command. rate reads limited clock protocol SMBus serial interfacing. System management software running processor microcontroller acquire data from thermal sensor system management. Upper lower thermal reference thresholds individually programmed thermal diode. register which holds single byte result also sampled comparator circuits. These circuits compare single byte result against programmable threshold bytes. alert signal Pentium Xeon processor (SMBALERT#) will assert when either threshold crossed. thermal byte reading also used conjunction with Thermal Reference Byte Processor Information ROM. Byte Processor Information contains address this byte, described more detail Section thermal byte reading from thermal sensor compared this Thermal Reference Byte provide indication difference between temperature processor core instant thermal byte reading temperature processor core under steady state conditions high power maximum TPLATE specifications. nominal precision least significant thermal byte
1.1.
EEPROM electrically erasable, programmable readonly memory; memory device that used store additional information, including information thermal solution. Processor Information memory device where Thermal Reference Byte other information stored. SMBus System Management bus. Thermal byte reading reading from thermal sensor. This byte represents core thermal data instant reading taken. Threshold byte value threshold value customized particular operating conditions. Thermal diode diode located processor core which enables thermal measurements. Thermal Reference Byte byte value that corresponds maximum operating TPLATE maximum steady state power specifications which product guaranteed operate. This byte determined during manufacturing test each processor unit stored Processor Information ROM. Thermal sensor device which performs analog digital conversions supplies single byte reading thermal data (from thermal diode).
3.0.
THERMAL REFERENCE
2.0.
THERMAL SENSOR
Pentium Xeon processor thermal sensor provides means acquiring thermal data from processor core with exceptional degree precision. thermal sensor composed control logic, SMBus interface logic, precision analog-to-digital converter, precision current source. thermal sensor drives small current through junction thermal diode located same silicon processor core. forward bias voltage generated across thermal diode sensed precision converter derives single byte data, "thermal byte reading." conversions occur continuously single byte result most recent conversion stored register thermal sensor. This single byte result read from register using serial interface protocol SMBus. thermal byte reading thermal diode
increase usefulness thermal diode thermal sensor, Intel included procedure manufacturing test flow Pentium Xeon processor. This procedure determines Thermal Reference Byte value programs into Processor Information ROM. Thermal Reference Byte uniquely determined each unit. procedure causes each unit dissipate maximum power (which vary from unit unit) while same time maintaining thermal plate maximum specified operating temperature. value Thermal Reference Byte determined individually each unit during manufacturing test. While processor runs code designed draw high power thermal plate forced maximum specified temperature, readings taken from thermal sensor determine Thermal Reference Byte. expected value this byte Processor Information falls within wide range. Contributing factors this wide range
values include variability between processors power consumption, ideality factors (see Section 4.1), junction plate thermal resistance (JP).
AP-914
thermal sensor limit programming shutdown action. Examples described further Section 3.3.
3.1.
Using Scratch EEPROM Thermal Management
3.3.
Application Examples
Thermal Reference Byte provided Processor Information Intel used calculate additional information thermal solution, which then stored Scratch EEPROM, desired. Thermal Reference Byte need used exists Processor Information ROM. Other creative applications this feature include deriving alternative (threshold byte value) which better tuned particular application. discussion these applications provided Section 3.3.
Note that application examples described Sections 3.3.1 through 3.3.4, maximum thermal plate temperature remains governing condition guaranteed correct functionality S.E.C. cartridge processor. 3.3.1. STANDARD OPERATION
3.2.
Calibration
There calibration required effectively apply this technology. Traditional methods calibration against absolute temperature scale applied with conventional methods. However, this necessary method used programming Thermal Reference Byte incorporates built-in calibration process variation. 3.2.1. PROCESSOR LEVEL
simplest take thermal byte readings compare them Thermal Reference Byte. delta between these readings approaches zero, actions taken gracefully shut down take other system-level action preserve data integrity. proportional delta, well rate change (derivative), even cumulative (integral) this delta used more sophisticated closed loop system optimal thermal management. 3.3.2. CUSTOMIZED THRESHOLD BYTES SYSTEM COOLING DEPENDENC
Dimensionless byte values corresponding meaningful system application conditions provide direct efficient method establishing thresholds thermal management software. Intel preprograms dimensionless threshold unique each processor form Thermal Reference Byte. Section describes applications that Thermal Reference Byte real time thermal byte readings, which applied produce superior total thermal solutions. 3.2.2. SYSTEM LEVEL
Thermal byte readings nominal and/or maximum system operating conditions taken compared Thermal Reference Byte. This delta proportional temperature difference. customized information programmed into nonvolatile memory, including Scratch EEPROM, used basis operations such
Consider changing above scenario using system level cooling thermal plate which maintains thermal plate temperature significantly below maximum TPLATE specification. Clearly, thermal byte readings will approach Thermal Reference Byte until sometime after onset potentially catastrophic event, late begin safe system shutdown other reactive procedures. Under these conditions, assuming application calls earliest possible detection onset potentially catastrophic event, establishing threshold byte value customized unique operating environment conditions advised. Just application described Section 3.3.1, delta approaches zero actions taken perform safe shutdown other appropriate system-level action. This will allow earliest response onset possible problem even particular case superior cooling system. 3.3.3. SYSTEM MANAGEMENT SOFTWAR
Through system management features, systems designed react sooner than
AP-914
3.4.2. CONTROL THEORY SMBALERT# EARLY DETECTION MECHANISM Different uses delta function primary concern depending particular situation. temperature slowly approaching threshold, value primary concern delta. However, temperature rapidly approaching threshold would want monitor rate (d/dt) order react quickly anticipation possible problem depending value Furthermore, rate (d/dt) relatively unchanging temperature near threshold, time integral taken desired push operating envelope. Indeed, choice proportional integral differential gain factors once again customized choice particular application environment processor power consumption response application software. 3.4.3. RESPONSE TIME INITIATE SHUTDOWN
possible with previous thermal alert systems. System management software used optimize timing detection onset potential problem specific operating conditions. This software time update threshold byte values that individualized threshold appropriate value current operating conditions. 3.3.4.
above applications SMBus bandwidth necessary take thermal byte readings. avoid wasteful bandwidth, asynchronous interrupt signal, SMBALERT#, used. avoid need poll each processor continuously, early warning programmed into thermal reference thresholds. This will cause SMBALERT# signal sensed system management microcontroller processor, early warning used cause system management hardware software begin monitoring thermal byte values. After brief period monitoring thermal byte readings, system management software select whether event that triggered early warning alert potential problem event false alarm, take corrective action clear alert appropriate.
3.4.
Filtering Thermal Sensor Readings
STATISTICAL ANALYSIS
Server management software which processes thermal byte reading should perform heavy damping filtering several hundred perhaps thousands data points (depending speed polling) before initiating graceful shutdown other system-level action. appropriate delay before responding will depend only time required graceful response sequence also time constant external thermal management system designed limit TPLATE within specified operating range. Using system even application specific characterization data, feasible adaptive values established coefficients filtering function. This will modulate delayed response, effectively customizing specific requirements system application.
3.4.1.
When using thermal sensor provide information thermal management software, care should taken ensure that harmless transient changes temperature construed indicating onset catastrophic conditions. quick response thermal diode temperature changes processor core will inevitably yield isolated transient readings that could misleading. should presumed that isolated byte reading indicative onset catastrophic thermal failure. Performing data analyses filtering effective tactic avoid false alarms. Relevant statistics such mean, standard deviation, mode, median, running average, minimum, maximum, etc. used. choice which combination these statistics optional different each system application. Statistical averaging using mean standard deviation effective method filtering thermal byte readings.
4.0.
PROCESSOR CORE THERMAL DIODE Ideality Factor
4.1.
thermal diode processor core Pentium Xeon processor. relationship junction diode described ideal diode equation:
4.2.
AP-914
where reverse saturation current kT/e volt-equivalent temperature. Maximum deviation particular diode from ideal behavior represented ideality factor. Ideality factors vary from diode diode. range ideality factors reason absolute temperature accuracy specified readings from thermal diode.
thermal plate temperature core being exercised high power mode. thermal diode located processor core does monitor cache temperature. complex relationship exists between core junction temperature plate temperature steady state. This relationship expressed equation: TJUNCTION TPLATE Power transient state, relationship much more complex typically expressed summation series step response functions. Each step response expressed equation:
Thermal Diode Thermal Plate Measurements
intimate internal thermal connection exists between on-core thermal diode most significant source thermal power. thermal diode temperature varies with processor core junction temperature much more closely than thermal plate, give earliest indication direction which TPLATE will move. This allows detection thermal variation onset thermal solution failure much sooner than thermocouple attached thermal plate, even thermal diode within cartridge itself. thermal mass core package, thermal grease, thermal plate, heatsink heat exchange device contribute slower response time thermal solutions that on-core thermal diode. slower response mask perturbation, which could potentially catastrophic event. Being earliest indicator possible problem, on-core thermal diode used temperature measurements provides tremendous benefit thermal management. Keep mind that maximum thermal plate specification remains governing condition guaranteed operation processor. some applications cache component driving
where initial temperature, final temperature, time constant which varies with each thermal solution. Figure illustrates slower response time thermal plate indicate temperature compared temperature core itself. This thermal data taken attaching thermocouple thermal plate directly above contact fingers with thermal tape. second thermocouple placed directly processor core package embedded between core heat slug cartridge thermal plate. cartridge temperature forced maximum specified condition. Various typical operations were performed shown Figure while thermal data collected thermal data logger.
AP-914
TPLATE CORE (seconds)
Thermal Reading
Figure Pentium® XeonThermal Plate Core Temperature Profiles
Figure illustrates, TPLATE response lags TCORE swings TCORE typically larger than swings TPLATE. microcontroller respond convenient asynchronous interrupt generator provided thermal alert signal (SMBALERT#). This potentially involve system management software begin sampling filtering thermal byte readings before determining whether shutdown other systemlevel action necessary. Many methods filtering series readings have been described effective strategies discerning between harmless transient spikes temperature actual indications thermal solution failure. Thermal Reference Byte present convenience feature programmed Intel each unit during manufacturing test. calibration required effectively apply this technology. Custom threshold byte values determined individual operating conditions desired, examples applications which this appropriate have been discussed. These unique threshold bytes allow earliest detection possible problem under specific operating conditions. Creative applications this features possible encouraged, especially they cater system's individual thermal solutions application conditions.
5.0.
CONCLUSION
Thermal management applications enabled become more flexible including thermal sensor located processor. thermal diode temperature changes with junction temperature much more closely than possible traditional thermal sensors. Thus, thermal sensor core provides earliest indication thermal variation onset thermal solution failure. This enables server management software invoke timely response onset potentially catastrophic event gracefully shutdown take other measures order preserve data integrity. Keep mind that maximum thermal plate specification remains governing condition guaranteed operation processor.

AP-914 APPLICATION Order Number: 245098-001 Information this

Top Searches for this datasheet

Other recent searches