TS32101

Final Datasheet

Rev 2.1

January 26, 2016

www.semtech.com

11 of 12

Semtech

Inamulti-layerboardapplication,thethermalviasaretheprimarymethodofheattransferfromthepackagethermalpadto

theinternalgroundplane.Theefficiencyofthismethoddependsonseveralfactors,includingdiearea,numberofthermalvias,

thicknessofcopper,etc.

Theabovedrawingisarepresentationofhowtheheatcanbeconductedawayfromthedieusinganexposedpadpackage.Each

applicationwillhavedifferentrequirementsandlimitationsandthereforetheusershouldusesufficientcoppertodissipatethe

powerinthesystem.Theoutputcurrentratingforthelinearregulatorsmayhavetobede-ratedforambienttemperaturesabove

85C.Thede-ratevaluewilldependoncalculatedworstcasepowerdissipationandthethermalmanagementimplementationin

theapplication.

Application Using A Single Layer PCB

Use as much Copper Area

as possible for heat spread

Package Thermal Pad

Package Outline

LayoutrecommendationsforaSingleLayerPCB:utilizeasmuchCopperAreaforPowerManagement.Inasinglelayerboard

applicationthethermalpadisattachedtoaheatspreader(copperareas)byusinglowthermalimpedanceattachmentmethod

(solderpasteorthermalconductiveepoxy).

Inbothofthemethodsmentionedaboveitisadvisabletouseasmuchcoppertracesaspossibletodissipatetheheat.

IMPORTANT:

IftheattachmentmethodisNOTimplementedcorrectly,thefunctionalityoftheproductisnotguaranteed.Powerdissipation

capabilitywillbeadverselyaffectedifthedeviceisincorrectlymountedontothecircuitboard.

Mold compound

Die

Epoxy Die attach

Exposed pad

Solder

Thermal Vias with Cu plating

Single Layer, 2oz Cu

Ground Layer, 1oz Cu

Signal Layer, 1oz Cu

Bottom Layer, 2oz Cu

20% Cu coverage

90% Cu coverage

5% - 10% Cu coverage

Note: NOT to Scale