Datasheet

LM22679/LM22679Q

SNVS581K –FEBRUARY 2013–REVISED NOVEMBER 2012

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The regulator has an exposed thermal pad to aid power dissipation. Adding multiple vias under the device to the

ground plane will greatly reduce the regulator junction temperature. Selecting a diode with an exposed pad will

also aid the power dissipation of the diode. The most significant variables that affect the power dissipation of the

regulator are output current, input voltage and operating frequency. The power dissipated while operating near

the maximum output current and maximum input voltage can be appreciable. The junction-to-ambient thermal

resistance of the LM22679 will vary with the application. The most significant variables are the area of copper in

the PC board, the number of vias under the IC exposed pad and the amount of forced air cooling provided. A

large continuos ground plane on the top or bottom PCB layer will provide the most effective heat dissipation. The

integrity of the solder connection from the IC exposed pad to the PC board is critical. Excessive voids will greatly

diminish the thermal dissipation capacity. The junction-to-ambient thermal resistance of the LM22679 PFM

package is specified in the Electrical Characteristics table. See application note AN-2020 for more information.

PCB Layout Example

Product Folder Links: LM22679/LM22679Q