Specifications and information are subject to change without notice.

2003-11

Sumitomo Electric Industries, Ltd. 1,Taya-cho, Sakae-ku, Yokohama, 244-8588 Japan

Phone: +81-45-853-7263 Fax: +81-45-853-1291

-10-

Technical Note

P0120004P

1.5W GaAs Power FET (Pb-Free Type)

SUMITOMO ELECTRIC

[Using Heat Sink]

The junction temperature can be calculated by the following

formula.

If you cannot get the junction temperature lower than the

absolute maximum rating only with the plated thru holes,

then you need to employ the heat sink. Attaching the heat

sink directly under pin 4 of the device improves the thermal

resistance between junction and ambient.

Generally, there are two ways of heat radiation. One is the

plated thru hole and the other is the heat sink. Key points will

be illustrated in each case below. Note that no measure

against oscillation is adopted in the figures. In the design of

circuit and layout, you should take stabilizing into account if

necessary.

[Using Thru Hole]

G

device.

for 2.5 M achine Screws

Package Outline

4-R0.3

Heatsink

2

1.9

×2.85

(4-R0.3)

for 2.5 M achine Screws

Grand Plane

rand Plane

pin (pin 4) as possible. The PCB is screwed on the

mounting plate or the heat sink to lower the thermal

resistance of the PCB.

[Note]

performance. Drills of the recommended diameters should

be used in the fabrication of vias.

holes around pin 4 of the device.

near the part to ensure optimal thermal performance.

the application circuit examples should be connected to

the device, although it is not shown in the figure below.

board to heat sink. Ensure that the ground/thermal via region

contacts the heat sink.

region where the board contacts the heat sink.

for 2.5 Machine Screws

Package Outline

Keepout

for 2.5 Machine Screws

Grand Plane

for 2.5 Machine Screws

Package Outline

Keepout

for 2.5 Machine Screws

Grand Plane

construction.