132:), is imminent, measures such as clock gating, clock stretching, clock speed reduction and others (commonly referred to as thermal throttling) are applied to prevent the temperature to raise further. If the applied mechanisms are not compensating enough for the processor to stay below the junction temperature, the device may shut down to prevent permanent damage.
34:
in an electronic device. In operation, it is higher than case temperature and the temperature of the part's exterior. The difference is equal to the amount of heat transferred from the junction to case multiplied by the junction-to-case
469:
78:) is specified in a part's datasheet and is used when calculating the necessary case-to-ambient thermal resistance for a given power dissipation. This in turn is used to select an appropriate
237:
490:. For example, a typical white LED output declines 20% for a 50 °C rise in junction temperature. Because of this temperature sensitivity, LED measurement standards, like
301:
491:
105:, the core temperature is measured by a network of sensors. Every time the temperature sensing network determines that a rise above the specified junction temperature (
384:
330:
266:
160:
130:
59:. At the low end, sensor diode noise can be reduced by cryogenic cooling. On the high end, the resulting increase in local power dissipation can lead to
501:
Junction heating can be minimized in these devices by using the
Continuous Pulse Test Method specified in LM-85. An L-I sweep conducted with an
495:
344:
Many semiconductors and their surrounding optics are small, making it difficult to measure junction temperature with direct methods such as
355:
Junction temperature may be measured indirectly using the device's inherent voltage/temperature dependency characteristic. Combined with a
394:
current pulses. This difficulty can be overcome by combining high-speed sampling digital multimeters and fast high-compliance pulsed
603:
563:
532:
410:
502:
387:
167:
47:
Various physical properties of semiconductor materials are temperature dependent. These include the diffusion rate of
619:
698:
668:
486:
junction temperature (Tj) is a primary determinate for long-term reliability; it also is a key factor for
98:
83:
27:
479:
349:
522:
487:
273:
402:
36:
555:
Fractional Order
Differentiation and Robust Control Design: CRONE, H-infinity and Motion Control
599:
559:
52:
553:
527:
498:, require that the junction temperature is determined when making photometric measurements.
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138:
108:
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measurements. However, this measurement technique is difficult to implement in multi-LED
510:
395:
56:
692:
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31:
345:
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Yellow LED shows that Single Pulse Test Method measurements yield a 25% drop in
483:
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technique such as JESD 51-1 and JESD 51-51, this method will produce accurate
21:
79:
102:
87:
48:
356:
94:
401:
Once junction temperature is known, another important parameter,
669:"3 Steps to Improved LED Light Measurements: Accuracy - Vektrex"
579:
Rudolf Marek, "Datasheet: Intel 64 and IA-32 Architectures",
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due to high common mode voltages and the need for fast, high
464:{\displaystyle R_{\theta }={\frac {\Delta T}{V_{f}I_{f}}}}
645:"Thermal Measurements Products & Solutions - Vektrex"
63:
that may cause transient or permanent device failure.
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365:
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620:"Measuring LED Junction Temperature (Tj) - Vektrex"
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Thermal and Power
Management of Integrated Circuits
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405:, may be calculated using the following equation:
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324:
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260:
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357:Joint Electron Device Engineering Council (JEDEC)
232:{\displaystyle T_{J}=T_{A}+(R_{\theta JA}P_{D})}
135:An estimation of the chip-junction temperature
93:In modern processors from manufacturer such as
474:Junction temperature of LEDs and laser diodes
162:can be obtained from the following equation:
82:if applicable. Other cooling methods include
8:
513:Test Method measurements yield a 70% drop.
303:= junction to ambient thermal resistance
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594:Vassighi, Arman; Sachdev, Manoj (2006).
67:Maximum junction temperature calculation
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268:= ambient temperature for the package
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598:. Integrated Circuits and Systems.
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14:
336:Measuring junction temperature (T
583:Vol.3A: System Programming Guide
552:Sabatier, Jocelyn (2015-05-06).
332:= power dissipation in package
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55:and the thermal production of
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296:{\displaystyle R_{\theta JA}}
533:Metal Semiconductor Junction
72:Maximum junction temperature
581:Software Developer's Manual
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558:. Springer. p. 47.
403:thermal resistance (Rθ)
74:(sometimes abbreviated
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84:thermoelectric cooling
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379:{\displaystyle T_{J}}
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325:{\displaystyle P_{D}}
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261:{\displaystyle T_{A}}
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155:{\displaystyle T_{J}}
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125:{\displaystyle T_{J}}
28:operating temperature
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24:junction temperature
17:Junction temperature
523:Safe operating area
43:Microscopic effects
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53:carrier mobilities
37:thermal resistance
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26:, is the highest
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61:thermal runaway
57:charge carriers
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699:Semiconductors
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30:of the actual
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565:9789401798075
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507:luminous flux
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346:thermocouples
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32:semiconductor
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676:. Retrieved
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628:. Retrieved
626:. 2017-01-06
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528:P-N Junction
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19:, short for
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509:output and
678:2017-10-17
654:2017-10-17
630:2017-10-17
539:References
488:photometry
392:duty cycle
51:elements,
22:transistor
431:Δ
420:θ
283:θ
206:θ
80:heat sink
693:Category
517:See also
103:Qualcomm
88:coolants
673:Vektrex
649:Vektrex
624:Vektrex
241:where:
602:
562:
49:dopant
503:Osram
496:LM-85
492:IESNA
95:Intel
76:TJMax
600:ISBN
560:ISBN
348:and
86:and
494:’s
482:or
480:LED
478:An
99:AMD
695::
671:.
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622:.
511:DC
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90:.
39:.
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454:f
450:I
444:f
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434:T
425:=
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372:J
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340:)
338:J
318:D
314:P
289:A
286:J
279:R
254:A
250:T
227:)
222:D
218:P
212:A
209:J
202:R
198:(
195:+
190:A
186:T
182:=
177:J
173:T
148:J
144:T
118:J
114:T
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.