1、JEDEC STANDARD Thermal Resistance Measurements of Conduction Cooled Power Transistors JESD313B (Revision of EIA-313-B formerly RS-313-B) OCTOBER 1975 (Reaffirmed: APRIL 1981, APRIL 2001) JEDEC SOLID STATE TECHNOLOGY ASSOCIATION NOTICE JEDEC standards and publications contain material that has been p
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5、ion included in JEDEC standards and publications represents a sound approach to product specification and application, principally from the solid state device manufacturer viewpoint. No claims to be in conformance with this standard may be made unless all requirements stated in the standard are met.
6、 Inquiries, comments, and suggestions relative to the content of this JEDEC standard or publication should be addressed to JEDEC at the address below, or call (703) 907-7559 or www.jedec.org Published by JEDEC Solid State Technology Association 2003 2500 Wilson Boulevard Arlington, VA 22201-3834 Thi
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9、d number of copies through entering into a license agreement. For information, contact: JEDEC Solid State Technology Association 2500 Wilson Boulevard Arlington, Virginia 22201-3834 or call (703) 907-7559 FOREWORD This standard describes a recommended test method for measuring the thermal resistance
10、 of conduction-cooled power transistors. This method is offered as a replacement for that contained in EIA/NEMA Standard RS-313-A (March 1968) which has been found deficient in its test method detail. The present method is the emitter-base forward voltage method with emitter-base switching and treat
11、s the detail circuitry, test instruments, calibration and precautions to assure relialde and rcproducihle mcasurcment. It generally conforms to the principle of MIL-STD.750 Method 3131 and to IEC Publication 147X2 Method 12.3.1. However, experience has shown that the test Performed under this Standa
12、rd is apphcahle to all power transistors regardless of thermal response times. This material was Prepared by JEDEC Committee JC-25 on Power Transistors and approved fo r publication by the JEDEC Solid State Products Council. RS-313-B Page 1 THERMAL RESISTANCE MEASUREMENTS OF CONDUCTION COOLED POWER
13、TRANSISTORS (From Stondnrds Proposal No. I 179, formulated under the cognizance of the JC-25 JEDEC Committee on Power Transistors.) 1. THERMAL RESISTANCE, JUNCTION to SPECIFIED REFERENCE POINT (ReJR). 1. I General Considerations. Of the thermal characteristics of a semiconductor device, the most fre
14、quently specified parameter is the thermal resistance between the chip and a reference point such as the device case or ambient. The thermal resistance of a semiconductor device is a measure of the ability of its mechanical structure (package) to provide for heat removal from the semiconductor junct
15、ion. In most devices, the maximum junction temperature cant be measured directly since the area of interest is not accessible due to packaging considerations. Thus, indirect means are used to infer the temperature of a specific area on the chip. The thermal resistance of a semiconductor device is th
16、erefore determined hy the measurement of a temperature-sensitive electrical parameter of a semiconductor junction within the device. The measured thermal nxistanct: of semiconductor clemcnts (transistors) is not constant as frequently assumed, IJI depends on the drvice operating conditions, the junc
17、tion and reference point temprratures, and the temperatura-sensitive parameter chosen. When specifying thermal resistance, it is therrforc important to indicate clearly the measuring conditions. The temperature sensitive device paramctcr is used as an indicator of an average (weighted) junction temp
18、erature of the semiconductor clement for calculations of thermal resistance. In measuring power transistor thrrmal resistance, either the emitter-base forward voltage or the collector-base forward voltage can bc used as the temperature sensitive electrical parameter to indicate the junction temperat
19、ure. Although equally precise, the Emitter-Base Voltage Technique has been found to be more accurale than the Collector-Base Voltage Technique, i.e., the Emitter- Base Voltage Technique gives a junclion temperature closer to the actual peak temperature on the chip. The greater inaccuracy of the Coll
20、ector-Base Voltage Technique is due to the greater deviation hctwcen the region of the colleclor junction traversed by the measuring current during calibration and the region traversed during test. 1.2 The Measurement of Thermal Resistance, Junction to Specified Reference Point (ReJR), using the emi
21、tter-base voltage of a transistor in the emitter-only switching mode as the temperature sensitive parameter. 1.2.1 Pwpose. The purpose of the test is to measure the junction to specified reference pain1 lhermal resistance of single element transistors by using the emitter-base junction to indicate t
22、hr device junction temperature. This method is to he used as the standard RS-313.B Page 2 technique, i.e., referee method for the measurement of thertmd resistanct:. Rowever, the procedure is also adaptable to production testing, including die attachment screwing (see Appendix A). 1.2.2 Irocedure. I
23、n mc:;muring transistor thernnd resistance, the emitter-base forward voltage of the transistor is used as the temperature sensitive parameter (TSP) to indicate the junction temperature. The TSP is measured at a small fixed forward current. This low level current, at which the temperature sensitive p
24、arameter is measured, is called the measuring or calibration current (IM). The magnitude of IM is such that the TSP varies linearly with temperature and is stahle. The TSP is measured under two geueral operating conditions. First, the mrasuremeuta of the emitter-base forward wItage necessary to dete
25、rmine the chauges iu the TSP due tr, the ditor in watts. Magnitude of lower heating power applied 10 tr.urjiator iu watls. Value of TSP corresponding to the temperature oT I,!K junction heated by P2 and measured at lM in millivolts. Value of TSP corresponditig to the tempr.ruturc of the junction Inx
26、ted by Pl and measured at IM iii millivolts. Beating power duty factor. RS-313-B Page 3 = Temperature sensitive parameter temperature coefficient measured at lM in millivolts/degree Celsius. TMC MC = Calibration temperature measured at reference point in degrecsCelsius. = Value of TSP during calibra
27、tion at lM and specific value of TMc in millivolts. If the lower heating power (P,) applied to the transistor is equal to the power dissipation during calibration then VMl = V,MC (for TMC= TR). Also, if the power dissipation during calibration is negligible, then PI-O. R8 JR can then be simplified t
28、o: R OJR= vM2 - VMC (for TMC = TR) x *“MC -1 I2D c 1 r MC Calihration Measurements of TR and TMC are made by means of a thermocouple attached to the reference point. See Appendix B for information on reference point tcmperaturc measurements of conduction cooled power transistors. The power dissipati
29、on in the device u the collector-emitter voltage being equal to that value used during the calibration procedure. During the interval between heating pulses (generally less than or equal to 250 /.ts), and with the constant measuring current (In,) and collector-emitter voltage (VCE) applied, the valu
30、e of the temperature sensitive parameter (VM2) is measured. When measuring the thermal resistance of a transistor, only the emitter current is switched from the heating to measuring mode. RS-313-B Page 4 It would be dcsirablc to measure the temperature sensitive parameter at the exact instant that t
31、he heating power removal is initiated since the junction temperature is maximum at that time. Ilowever, this is not possible for the following reasons: 1. It takes a finite time for the transistor current to decay from the heating value to the measuring value. 2. Transients exist in the measuring vo
32、ltage waveform for some time after the measuring current value is reached due primarily to charge storage effects in the device under test. The measuring voltage cannot be used as an indicator of junction temperature until after these transients r&side. The delay time before the TSP can be measured
33、ranges from 5 to 100 ps for most transistors. Since some semiconductor element cooling occurs between the time that the heating power is removed and the time that the TSP is measured, the junction temperature value determined from the TSP will be in error leading to a deceptively lower calculated th
34、ermal re- sistance. It may therefore hc: necessary to extrapolate the measured junction temperature back to the time whcrc the heating power was terminated ascd on the shape of the cooling waveform beyond the measuring point (see Appendix C for details). The extrapolated value, either in terms of th
35、e TSP in millivolts or in terms of the actualcalculated temperature in degrres Celsius, should then be used in the calculation of thermal rrsistancc. It is recommended tha1 the Powrr Application Test he performed so that the test device junction temperature is rcprcscntativc of worse case usage. Con
36、sistent with this, the refcrcncc point temperature should hc such that the generated junction-to-cast temperature difference is greater than or equal to 30% The lyre of heat dissipator used for the Power Application tent must he chosen to accomplish this. The v&es of V Application Test. M2, VMC, P2,
37、 and D are recorded during the Power The same v&c of collc!c1or-emitter voltage used during the Power Application Test for internal device heating purposes is also applied during the Calibration Procedure (see Step 2). Step 2 - Measurement of the Temperature Coefficient of the TSP. The tempcraturc c
38、oefficient of the temperature scnsitivr parameter is generated by measuring the TSP as a function of the reference point temperature, for a specified constant measuring or calibration current (lM) and collector-emitter voltage (V CE), by externally heating lhe device under test in an oven or on a te
39、mperature controlled hca&ink. At small currents, the transistor emitter-base voltage decrcascs with increasing temperature. A measuring current ranging from 1.0 to 50 mA is generally used, dc,prnding on the rating and operating conditions of the device under test, for measuring the TSP. The measurin
40、g current is generally picked such that the TSP varies linearly with temperature over the range of interest and that negligible internal heating (PI = 0) occurs during the measuring interval. Therefore, the reference point temperature is approximately equal to the junction temperature during calibra
41、tion. The value of the TSP temperature coefficient (*VhIC/* TMC)? for the particular measuring current and collector-emitter voltage used in the test, is calculated from the cahhration curve. RS-313-B Page 5 1.23 Test Conditions to be Specified 1. Case Temperature range during calibration. 2. Measur
42、ing or calibration current. 3. Heating current magnitude. 4. Heating (collector) voltage magnitude. 5. Heating power duty factor. 6. Heating power repetition rate. 7. Delay time before measurement of TSP. 8. Total heating time duration. 9. Reference temperature measuring point. 10. Reference point t
43、emperature for heating power measurements. 11. Mounting torque. 12. Mounting arrangement. 13. Extrapolation procedure. CHARACTERISTIC TO BE MEASURED Thermal Resistance, Junction to Specified Reference Point (ReJR). Two of the most common thermal r&stance specifications are: . ROJC - Thermal rcsistan
44、cr from junction to case. 2. RoJM- Thermal rcsislancc from junction to mounting surface. RS-313-B Page 6 1.2.4 Test Circuit PULSE Notr: Lossy fcrritc hrnds may III: required on the cmittcr and base lcads of t,hc device under test to prcvcmt oscillations. A capacitor may also be required between the
45、collector and ground of the dcvicr under test to prevent oscillations. The circuit is controlled lay a clock pulsr width of approximately 250 ps * and a rrpcti1ion rate of approximately 4 llz *. When the voltage level of the clock pulse is zero, the: transistor Ql is off and the current through the
46、transistor under test (TUT) is the sum of the heating current (switch Sl closed) and the measuring current (lM). The heating current is furnished by the VEE supply, and the measuring current by the V hlhl supply. At the end of each heating power pulse the clock assumes a specified non-zero level for
47、 a period of time that is short compared with the hrating interval. This is sufficient to hias the lransistor Ql on, which reverse biases the diode Dl so that the heating current no longer passes through the device under test. The function of the regulator Zener) diode Zl (optional) is to decrease t
48、he switching time of the: device under test. The regulator voltage Vz of the diode Zl should be equal to or less than the maximum rated VEBO of the transistor under test. After a delay, usually 5 to 100 6, the sample-and-hold unit (S & I) senses the TSP, i.e., VM2, for a 1.5 /.IS * period and displa
49、ys its value on the digital voltmeter (DVM). Ilie trmpcrature coefficient of the TSP and the required voltage VMc (for TMC = TR) are obtained hy making the required measurements with the heating curren1 supply disconnected (switch Sl open). The digital vollmetcr used to measure the TSP can also be used to measure the power dissipation of the device under test by connecting it across the junction(s) to measure the voltage(s), a.111 across a suitehlc non-inductive current sensing resistor(s) to measure the current(s). * Typical V&K RS-313-B Page 7 APPENDIX A Thermal Response Mea
