IRU1502-33

9

Rev. 1.0

07/17/03

www.irf.com

8C

DT = 116.48C

The thermal pad of MLPM is connected to a 1 inch square

copper through vias for a four layer PCB board design.

From the datasheet, this thermal junction-to-ambient re-

sistance is given as:

For IRU1502-33, the thermal design needs to be con-

sider so that the resultant junction temperature is lower

than the maximum operating temperature, which is 125

8C.

Therefore:

Assuming, the following conditions:

Calculate the maximum power dissipation using the fol-

lowing equation:

For MLPM package, we have:

Layout Consideration

The IRU1502-33, like many other high-speed regulators,

requires that the output capacitors be close to the de-

vice for stability. For power consideration, a ground plane

pad of approximately one-inch square on the compo-

nent side must be dedicated to the device where all

ground pins are connected to dissipate the power. If a

multilayer board is used, it is recommended that the

inner layers of the board are also dedicated to the size

of the pad for better thermal characteristics.

Where:

3(5 - 3.3) = 1.7W

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Data and specifications subject to change without notice. 02/01