Sun Microsystems SME5224AUPA-400 manual Case Temperature Measuring Method

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UltraSPARC™-II CPU Module	Advanced Version
400 MHz CPU, 4.0 MB E-Cache	SME5224AUPA-400

Case Temperature Measuring Method

The relationship between case temperature and junction temperature is described in the following thermal equation.

If Tc is known, then Tj can be calculated:

Tj = Tc + (Pd x θjc)

Note: Testing is done with the worst-case power draw, software loading, and ambient air temperature.

There is good tracking between the case temperature and the heatsink temperature.

Heatsink Temperature Measuring Method

Measuring the heatsink temperature is sometimes easier than measuring the case temperature. This method provides accurate results for most designs. If the heatsink temperature (Ts) is known then the following ther- mal equation can be used to estimate the junction temperature:

Tj = Ts + [Pd (θjc + θcs)]

July 1999

Sun Microsystems, Inc

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Contents Module Description Module Features Module BeneﬁtsEase of System Design PerformanceCPU Features CPU Beneﬁts CPU DescriptionUltraSPARC-II CPU Data Buffer Description External Cache DescriptionUltraSPARC-II Data Buffer UDB-II Module Component Overview Block DiagramUPA Connector Pins System InterfaceUPA Interconnect Module Power Module IDJtag Interface Signal Type Name and Function Signal DescriptionSystem Interface Clock InterfaceMiscellaneous Signals JTAG/Debug InterfaceInitialization Interface System Clocks Module ClocksSystem Clock Distribution Tested CPU to UPAClock Signal Distribution Symbol Parameter Rating Units Electrical CharacteristicsSymbol Parameter Min Typ Max Units Absolute Maximum RatingsDC Characteristics Module Power ConsumptionSymbol Parameter Conditions Min Typ Max Units Module System Loading Example for UPADATA, Upaecc UPA Data Bus Spice ModelUpaclk Module Clocks Setup and Hold Time SpeciﬁcationsCpuclk Module Clock Clock BuffersPropagation Delay, Output Hold Time Speciﬁcations Timing Measurement WaveformsMin Max Unit CPU Module Components Mechanical SpecificationsCPU Module Side View Two Step Approach to Thermal Design Thermal SpecificationsTerm Deﬁnition Speciﬁcation Comments Thermal Deﬁnitions and SpeciﬁcationsAirﬂow Cooling Measurement Method Temperature Estimating and Measuring MethodsAir Velocity Speciﬁcations Air VelocityHeatsink Temperature Measuring Method Case Temperature Measuring MethodAC Characteristics Jtag Timing MHz CPU MHz TCK Symbol Parameter Signals ConditionsJtag Testability Jtag Ieee 1149.1 Timing Pin UPA Connector PIN Assignments TOP ViewVddcore GND Vddcore GND Vddcore UPAPORTID1 UPA Connector PIN Assignments Bottom ViewStorage and Shipping Specification Handling CPU ModulesValue Parameter Conditions Min Typ Document Revision History Ordering InformationPart Number CPU Speeds Description Date Document No ChangeSun Microsystems, Inc UltraSPARC -II CPU Module UltraSPARC-II CPU Data Buffer Description Block Diagram System Interface Module ID System Interface JTAG/Debug Interface UPA and CPU Clocks Clock Signal Distribution Absolute Maximum Ratings DC Characteristics UPA Data Bus Spice Model Upaclk Module Clocks Propagation Delay, Output Hold Time Speciﬁcations Mechanical Specifications CPU Module Side View Two Step Approach to Thermal Design Thermal Deﬁnitions and Speciﬁcations Temperature Estimating and Measuring Methods Case Temperature Measuring Method AC Characteristics Jtag Timing Jtag Ieee 1149.1 Timing UPA Connector PIN Assignments TOP View UPA Connector PIN Assignments Bottom View Storage and Shipping Specification Ordering Information Sun Microsystems, Inc