1、EIA/ JEDEC STANDARD Integrated Circuit Thermal Test Method Environmental Conditions = Forced Convection (Moving Air) JESD51-6 MARCH 1999 ELECTRONIC INDUSTRIES ALLIANCE JEDEC Solid State Technology Association Electronic Industries Alliance NOTICE EWJEDEC standards and publications contain material t
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7、sed to JEDEC Solid State Technology Association, 2500 Wilson Boulevard, Arlington, VA 2220 1-3834, (703)907-7560/7559 or www.jedec.org Published by ELECTRONIC INDUSTRIES ALLIANCE 1999 Engineering Department 2500 Wilson Boulevard Arlington, VA 2220 1-3834 “Copyright“ does not apply to JEDEC member co
8、mpanies as they are free to duplicate this document in accordance with the latest revision of JEDEC Publication 2 1 “Manual of Organization and Procedure“. PRICE: Please refer to the current Catalog of JEDEC Engineering Standards and Publications or call Global Engineering Documents, USA and Canada
9、(1-800-854-7179), International (303-397-7956) Printed in the U.S.A. All rights reserved PLEASE! DONT VIOLATE THE LAW! This document is copyrighted by the EL4 and may not be reproduced without permission. Organizations may obtain permission to reproduce a iimited number of copies through entering in
10、to a license agreement. For information, contact: Global Engineering Documents 15 Inverness Way East Engiewood. CO 801 12-5704 or call U.S.A. and Canada 1-800-854-7179, International (303) 397-7956 JEDEC Standard No. 5 1-6 INTEGRATED CIRCUIT THERMAL TEST METHOD ENVIRONMENTAL CONDITIONS - FORCED CONV
11、ECTION (MOVING AIR) Contents 1 Scope 2 Normative references 3 Definitions, symbols, and abbreviations 4 Specification of environmental conditions 4.1 Wind tunnel specifications 4.1.1 Flow uniformity 4.1.2 Swirl 4.1.3 Turbulence 4.1.4 Unsteadiness 4.1.5 Chiu?i“uer size 4.1.6 Temperature uniformity 4.
12、1.7 Performance verification 4.2 Testboard 4.3 Placement in the test section 4.3.1 Orientation 4.3.2 Measurement 4.3.3 Simultaneous testing 4.4 Test fixture support 4.5 Environmental conditions and measurements 4.5.1 Flow velocity measurement 4.5.2 Ambient temperature measurement 5 Thermal measureme
13、nt procedure and methodology 5.1 K factor calibration 5.2 Test start-up and initial equilibrium verification 5.3 Power level seiection and applying power 5.4 Verification of thermal steady-state and test completion 5.5 Verification of absence of interaction between applied power level and temperatur
14、e- sensitive parameter (optional procedure) 6 Thermal characterization parameters 6.1 Y JT Junction-to-top-center of the package (Optional procedure) 6.2 Y JT Junction-to-board (Optional procedure) 7 Test conditions to be reported Page 1 1 1 2 2 2 2 3 3 4 4 4 4 6 6 6 7 7 7 7 8 9 9 10 10 10 3 J 11 11
15、 11 12 -1- JEDEC Standard No. 5 1-6 INTEGRATED CIRCUIT THERMAL TEST METHOD ENVIRONMENTAL CONDITIONS - FORCED CONVECTION (MOVING AIR) Contents (concluded) Page Figures 1 Open circuit wind tunnel 2 minimum clearance 3 Test section 4 Horizontal air flow, horizontal board (Package up) 5 Horizontal air f
16、iow, vertical board orientation 6 Vertical air flow, vertical board 7 Thermocouple location Tables 1 Recriended pO“ kvds 2 Thermal measurement test conditions and data parameters 2 3 4 5 5 6 11 10 12 -11- JEDEC Standard No. 5 1-6 Page 1 INTEGRATED CIRCUIT THERMAL TEST METHOD ENVIRONMENTAL CONDITIONS
17、 - FORCED CONVECTION (MOVING AIR) (From JEDEC Board Ballot JCB-98-103, under the cognizance of the JC-15.1 Committee on Themal Characterization.) 1 Scope This standard specifies the environmental conditions for determining thermal performance of an integrated circuit device in a forced convection en
18、vironment when mounted on a standard test board. The thermal resistance measured using this document is RQJMA or BJMA. This methodology is not meant to and will not predict the performance of a device in an application-specific environment. 2 Normative references The following standards contain prov
19、isions that, through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standards are subject to evisin, anci pplcs i ageerxnts based ii :his s:dxd are ecruged te ivestigzte the pssiki!i nf “I applying the most recent ed
20、itions of the standards indicated below. JESDS i, “Methodology for the Thermal Measurement of Component Packages (Single Semiconductor Devices)“. This is the overview document for this series of specifications. JESD5 1-1, “Integrated Circuit Thermal Measurement Method - Electrical Test Method“. JESD
21、5 1-2, “Integrated Circuit Thermal Test Method Environmental Conditions - Natural Convection (Still Air). JESDS 1-3, “Low Effective Thermal Conductivity Test Board for Leaded Surface Mount Packages“. JESDS 1-4, “Themal Test Chip Guideline (Wire Bond Type Chip)“ JESDS 1-7, “High Effective Thermal Con
22、ductivity Test Board for Leaded Surface Mount Packages“ 3 Definitions, symbols, and abbreviations Refer to the documents JESD51, JESDSI-1 and JESD51-2 for a general list of terminology. JEDEC Standard No. 51-6 Page 2 Entrance and Settling Zone 4 Specification of environmental conditions Contraction
23、Section Transition Air Mover.(Fan) 4.1 Wind tunnel specifications Test Section Section A low velocity wind tunnel is shown in figure 1 as an example only. The package and test fixtures are not shown in this example. In most electronic applications, the wind tunnels are normally used at velocities le
24、ss than 10 m/s. The minimum specifications for acceptable wind tunnels are detailed in the following paragraphs. Normally the manufacturer of the wind tunnel will characterize the wind tunnel to certify performance to these specifications. The wind tunnel is characterized without the test board and
25、package. “Honeycomb“ Flow Straighteners and Screens Figure 1 - Open circuit wind tunnel This type of tunnel (Eiffel type, fan at downstream end of system) is also commonly called a suction or indraft style. A radiused inlet prevents separation of the flow from the settling length walls. The flow man
26、agement components include a honeycomb, which reduces lateral velocity differences, and screens which, owing to their higher pressure drop in the flow direction, promote a more uniform axial velocity. The combined effect of these elements is the reduction of turbulence intensity and production of a
27、flat velocity profile. A contraction duct is employed to accelerate the flow while maintaining flow quality. The diffusedtransfonnation conveys the flow from the test section to the circular fan inlet. Proper selection of diffuser angles helps to prevent flow separation which would create unsteadine
28、ss. A flow- through tunnel (Wenham type) incorporates similar design features. 4.1.1 Flow uniformity The flow velocity shall be uniform to +/-5% of the mean velocity across the central 90% of the test chamber cross-section, and constant within +/-5% along the length of the test section. 4.1.2 Swirl
29、The cross stream component (swirl) of the mean flow shall be less than 5% of the mean flow velocity. The cross stream component of the mean flow is measured with a three axis or cross wire anemometer capable of measuring flow in a minimum of two directions. JEDEC Standard No. 5 1-6 Page 3 4.1 Wind t
30、unnel specifications (contd) 4.1.3 Turbulence The turbulence shall be less than 2%. The turbulence is measured with a hot wire anemometer with a frequency response of 10 kHz or higher. 4.1.4 Unsteadiness The unsteadiness (change in mean flow velocity) shall be less than 5% over the time period of a
31、typical measurement. 4.1.5 Chamber size The test section shall be large enough that the frontal area of the test sample (package, board, support fixture, and optional heat sink) shall be less than 5% of the wind tunnel cross sectional area. Adequate “bypass“ of the air is allowed around the test spe
32、cimen to avoid the channel flow (or “ducted“) regime. The minimum clearance on each side of the part is specified in figure 2. Wall effects are avoided if the wind tunnel test section dimension perpendicular to the plane of the test board is at least twice the flow length along the test board and th
33、e test board is mounted in the center of the wind tunnel. These dimensions are illustrated in figure 3. Minimum distances to the wall in both directions are reported in table 2. Using this specification, the measured thermal resistance will be largely independent of wind tunnel cross section dimensi
34、ons. = 2H 2H I I Clearance = 2 Clearance = 2W Figure 2 - Minimum clearance The minimum clearance around a package or around a package and heat sink is twice the width of the heat sink (or package whichever is larger) or twice the height of the heat sink plus package and board. In addition, the front
35、al area of the package, heat sink, test board, and fixture must be less than 5% of the cross section of the test section of the wind tunnel. The same rules apply for a wind tunnel with round section as illustrated with the dashed lines. JEDEC Standard No. 51-6 Page 4 _c + 4.1 Wind tunnel specificati
36、ons (contd) 4.1.5 Chamber size (contd) 7 It is recommended that the test section perpendicular distance be twice the flow length of the test board (h 2L). 4.1.6 Temperature uniformity The air temperature in an empty test section shall be uniform to +/- 1 OC. 4.1.7 Performance verification The perfor
37、mance of the wind tunnel to the above characteristics must be periodically checked. Typical causes of degradation in performance are sagging screens, dust in screens and honeycomb section, dust on the contraction duct, and fan damage such as bent blades or wobble in the fan bearings. Careful inspect
38、ion of the wind tunnel on a yearly basis will normally be sufficient. 4.2 Test board The test board specified in JESD51-3, and JESD51-7, which are appropriate for the device being tested, shall be used. It is essential that any reported data must specify the test board used if the data was not obtai
39、ned using the appropriate 1s test board 4.3 Placement in the test section The device that is mounted on the test board will be placed in the test section of the wind tunnel as described in figures 4,5, or 6. JEDEC Standard No. 51-6 Page 5 4 Specification of environmental conditions (contd) 1.3 Place
40、ment in the test section (contd) Thermocouple Device under Test _c + LTest Board Air Flow _c _c Support Rod _c Air Flow Optional _t + Extra Support Rod I Side View Device under Test %$I- _, Top View Figure 4 - Horizontal air flow, horizontal board (Package up) Device under Test Air Flow _c Thermoco
41、support Figure 5 - Horizontal air flow, vertical board orientation JEDEC Standad NO. 5 1-6 Page 6 4 Specification of environmental conditions (contd) 4.3 Placement in the test section (contd) Side 1 View X Side 2 View I Test Board / Device under Test t Air Flow Figure 6 - Vertical air flow, vertical
42、 board 4.3.1 Orientation The orientation of the printed circuit board and the flow direction of the wind tunnel must be specified when test data is reported. The printed circuit board is specified as horizontal or vertical orientation with the flow of air in the wind tunnel either horizontal or vert
43、ically upward. If the printed circuit board is horizontal, the pacliage being tested shall be on the upward-facing side of the board. 4.3.2 Measurement The measurement of thermal resistance in a horizontal wind tunnel with a horizontal orientation of the test board in a mixed convection mode will yi
44、eld thermal resistance measurements that will approach the values obtained using reference 3 as the mean flow velocity in the tunnel approaches zero. Testing in the vertical orientation will yield slightly lower thermai resistance values. Typically, at mean flow velocities above 2 m/s (about 400 fdr
45、nin), there will be no difference between the different orientations when the devices are at the surface temperatures produced by the power ranges specified in this document. 4.3.3 Simultaneous testing Simultaneous testing of more than one single-device board in the wind tunnel is possible if the de
46、vices are arranged such that the resulting thermal resistance measurement is within +/- 3% of the average value obtained when single devices are tested in the uniform velocity portion of the cross section. This qualification of the test methodology for a given lab must be done with a statistically s
47、ignificant number of samples. It should be tested on both the smallest device with highest thermal resistance and the highest power device with lowest thermal resistance being tested. JEDEC Standard No. 5 1-6 Page 7 4 Specification of environmental conditions (contd) 4.4 Test fixture support The pri
48、nted circuit board and device being tested must be supported with minimal obstruction to the air flow. The recommended support should lie in the plane of the board and be no thicker than the socket and not more than 20 mm longer than the socket. To minimize turbulence, leading and trailing edges of
49、the support should not have square edges. Because the support structure can act as an airfoil, it must be aligned with the air flow. CAUTION - The geometrical angle of attack of the printed circuit board with the air flow may cause significant differences in the measured thermal resistance. Normally a level is used to align the test section; then the angle of attack is determined using measurements of the distance from the leading and trailing edges to the test section wall. The board shall be aligned with the test section wall within +/-
