データシートサーチシステム |
|
LTM4653 データシート(PDF) 18 Page - Linear Technology |
|
LTM4653 データシート(HTML) 18 Page - Linear Technology |
18 / 32 page LTM4653 18 Rev 0 For more information www.analog.com APPLICATIONS INFORMATION Depending on the duty cycle of operation, the output volt- age ripple achieved by paralleled, synchronized LTM4653 modules may be considerably smaller than what is yielded by a single-phase solution. Application Note 77 provides a detailed explanation of multiphase operation (relevant to parallel LTM4653 applications) pertaining to noise reduction and output and input ripple current cancella- tion. Regardless of ripple current cancellation, it remains importantfortheoutputcapacitanceofparalleledLTM4653 applications to be designed for loop stability and transient response. LTpowerCAD is available for such analysis. Figure 3 illustrates the RMS ripple current reduction as a function of the number of interleaved (paralleled and synchronized) LTM4653 modules—derived from Ap- plication Note 77. Radiated EMI Noise The generation of radiated EMI noise is an inherent disad- vantageofswitchingregulators.Fastswitchingturn-onand turn-off of the power MOSFETs—necessary for achieving high efficiency—create high-frequency (~30MHz+) ∆l/∆t changes within DC/DC converters. This activity tends to be the dominant source of high-frequency EMI radiation in such systems. The high level of device integration within LTM4653—including optimized gate-driver and critical front-end � filter inductor—delivers low radiated EMI noise performance. Figures 4 to 6 show typical ex- amples of LTM4653 meeting the radiated emission limits established by EN55022 Class B. Thermal Considerations and Output Current Derating The thermal resistances reported in the Pin Configuration section of this data sheet are consistent with those pa- rameters defined by JESD51-12 and are intended for use with finite element analysis (FEA) software modeling tools that leverage the outcome of thermal modeling, simula- tion, and correlation to hardware evaluation performed on a µModule package mounted to a hardware test board. The motivation for providing these thermal coefficients is found in JESD51-12 (“Guidelines for Reporting and Using Electronic Package Thermal Information”). Manydesignersmayopttouselaboratoryequipmentanda testvehiclesuchasthedemoboardtopredicttheµModule regulator’s thermal performance in their application at various electrical and environmental operating conditions to compliment any FEA activities. Without FEA software, the thermal resistances reported in the Pin Configuration section are, in and of themselves, not relevant to providing guidance of thermal performance; instead, the derating curves provided in this data sheet can be used in a man- ner that yields insight and guidance pertaining to one’s application-usage,andcanbeadaptedtocorrelatethermal performance to one’s own application. The Pin Configuration section gives four thermal coeffi- cients explicitly defined in JESD51-12; these coefficients are quoted or paraphrased below: 1. θJA, the thermal resistance from junction to ambient, is the natural convection junction-to-ambient air thermal resistance measured in a one cubic foot sealed enclo- sure. This environment is sometimes referred to as “still air” although natural convection causes the air to move. This value is determined with the part mounted toaJESD51-9definedtestboard,whichdoesnotreflect an actual application or viable operating condition. 2. θJCbottom, the thermal resistance from junction to the bottom of the product case, is determined with all of the component power dissipation flowing through the bottom of the package. In the typical µModule regulator, the bulk of the heat flows out the bottom of the pack- age, but there is always heat flow out into the ambient environment. As a result, this thermal resistance value may be useful for comparing packages but the test conditions don’t generally match the user’s application. 3. θJCtop, the thermal resistance from junction to top of the product case, is determined with nearly all of the componentpowerdissipationflowingthroughthetopof the package. As the electrical connections of the typical µModule regulator are on the bottom of the package, it is rare for an application to operate such that most of the heat flows from the junction to the top of the part. As in the case of θJCbottom, this value may be useful for comparing packages but the test conditions don’t generally match the user’s application. |
同様の部品番号 - LTM4653 |
|
同様の説明 - LTM4653 |
|
|
リンク URL |
プライバシーポリシー |
ALLDATASHEET.JP |
ALLDATASHEETはお客様のビジネスに役立ちますか? [ DONATE ] |
Alldatasheetは | 広告 | お問い合わせ | プライバシーポリシー | リンク交換 | メーカーリスト 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 |