 |
Moteur de recherche de fiches techniques de composants électroniques |
|
|
Moteur de recherche de fiches techniques de composants électroniques |
|
TPS79401DGNRG4 Fiches technique(PDF) 10 Page - Texas Instruments |
|
||||||||||||||||||||||||||||||
TPS79401DGNRG4 Fiches technique(HTML) 10 Page - Texas Instruments |
|
|
10 / 23 page  www.ti.com THERMAL INFORMATION TJ A RθJC TC B RθCS TA C RθSA SOT223 Package CIRCUIT BOARD COPPER AREA B A C P D max + VIN(avg) * VOUT(avg) I OUT(avg) ) VI(avg) I Q T J + TA ) PD max RθJC ) RθCS ) RθSA (5) TPS794xx SLVS349E – NOVEMBER 2001 – REVISED DECEMBER 2005 The amount of heat that an LDO linear regulator generates is directly proportional to the amount of power it dissipates during operation. All integrated circuits have a maximum allowable junction temperature (TJmax) above which normal operation is not assured. A system designer must design the operating environment so that the operating junction temperature (TJ) does not exceed the maximum junction temperature (TJmax). The two main environmental variables that a designer can use to improve thermal performance are air flow and external heatsinks. The purpose of this information is to aid the designer in determining the proper operating environment for a linear regulator that is operating at a specific power level. In general, the maximum expected power (PDmax) Figure 24. Thermal Resistances consumed by a linear regulator is computed as shown in Equation 4: Equation 5 summarizes the computation: (4) where: The RΘJC is specific to each regulator as determined by its package, lead frame, and die size provided in • V IN(avg) is the average input voltage the regulator's data sheet. The RΘSA is a function of • V OUT(avg) is the average output voltage the type and size of heatsink. For example, black • I OUT(avg) is the average output current body radiator type heatsinks can have RΘCS values • I Q is the quiescent current ranging from 5 °C/W for very large heatsinks to 50 °C/W for very small heatsinks. The RΘ CS is a For most TI LDO regulators, the quiescent current is function of how the package is attached to the insignificant compared to the average output current; heatsink. For example, if a thermal compound is therefore, the term VIN(avg) x IQ can be neglected. The used to attach a heatsink to a SOT223 package, operating junction temperature is computed by RΘCS of 1°C/W is reasonable. adding the ambient temperature (TA) and the increase in temperature due to the regulator's power Even if no external black body radiator type heatsink dissipation. The temperature rise is computed by is attached to the package, the board on which the multiplying the maximum expected power dissipation regulator is mounted provides some heatsinking by the sum of the thermal resistances between the through the pin solder connections. Some packages, junction and the case (RΘJC), the case to heatsink like the DDPAK and SOT223 packages, use a (RΘCS), and the heatsink to ambient (RΘSA). Thermal copper plane underneath the package or the circuit resistances are measures of how effectively an board ground plane for additional heatsinking to object dissipates heat. Typically, the larger the improve their thermal performance. Computer-aided device, the more surface area available for power thermal modeling can be used to compute very dissipation and the lower the object's thermal accurate approximations of an integrated circuit's resistance. thermal performance in different operating environments (for example, different types of circuit Figure 24 illustrates these thermal resistances for a boards, different types and sizes of heatsinks, SOT223 package mounted in a JEDEC low-K board. different air flows, etc.). Using these models, the three thermal resistances can be combined into one thermal resistance between junction and ambient (RΘJA). This RΘJA is valid only for the specific operating environment used in the computer model. 10 Submit Documentation Feedback |
Numéro de pièce similaire - TPS79401DGNRG4 |
|
Description similaire - TPS79401DGNRG4 |
|
|
|
Lien URL |
| Politique de confidentialité |
| ALLDATASHEET.FR |
| ALLDATASHEET vous a-t-il été utile ? [ DONATE ] |
À propos de Alldatasheet | Publicité | Contactez-nous | Politique de confidentialité | Echange de liens | Fabricants All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
French ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
