MTB9N25E ON Semiconductor, MTB9N25E Datasheet - Page 9

• Manufacturer Part Number: MTB9N25E
• Description: Tmos Power Fet 9.0 Amperes, 250 Volts
• Manufacturer: ON Semiconductor

design. The footprint for the semiconductor packages must
be the correct size to ensure proper solder connection
function of the drain pad size. These can vary from the
minimum pad size for soldering to a pad size given for
maximum power dissipation. Power dissipation for a surface
mount device is determined by T
junction temperature of the die, R
from the device junction to ambient, and the operating
temperature, T
sheet, P
ratings table on the data sheet. Substituting these values into
the equation for an ambient temperature T
calculate the power dissipation of the device. For a D
device, P
the recommended footprint on a glass epoxy printed circuit
board to achieve a power dissipation of 2.5 Watts. There are
other alternatives to achieving higher power dissipation from
the surface mount packages. One is to increase the area of
the drain pad. By increasing the area of the drain pad, the
power dissipation can be increased. Although one can
Surface mount board layout is a critical portion of the total
The power dissipation for a surface mount device is a
The values for the equation are found in the maximum
The 50°C/W for the D
D
D
can be calculated as follows:
is calculated as follows.
INFORMATION FOR USING THE D
P
A
D
. Using the values provided on the data
P
= 150°C − 25°C
RECOMMENDED FOOTPRINT FOR SURFACE MOUNTED APPLICATIONS
D
=
2
50°C/W
PAK package assumes the use of
T
J(max)
POWER DISSIPATION FOR A SURFACE MOUNT DEVICE
R
θJA
J(max)
θJA
− T
10.66
0.42
= 2.5 Watts
, the thermal resistance
A
, the maximum rated
A
of 25°C, one can
0.33
8.38
http://onsemi.com
2
PAK
17.02
0.63
2
9
PAK SURFACE MOUNT PACKAGE
interface between the board and the package. With the
correct pad geometry, the packages will self align when
subjected to a solder reflow process.
almost double the power dissipation with this method, one
will be giving up area on the printed circuit board which can
defeat the purpose of using surface mount technology. For
example, a graph of R
Figure 16.
an aluminum core board such as Thermal Clad™. Using a
board material such as Thermal Clad, an aluminum core
board, the power dissipation can be doubled using the same
footprint.
°
Another alternative would be to use a ceramic substrate or
0.12
3.05
70
60
50
40
30
20
Figure 16. Thermal Resistance versus Drain Pad
0
Area for the D
2
2.032
1.016
0.08
0.04
2.5 Watts
3.5 Watts
4
6.096
0.24
θJA
A, Area (square inches)
5 Watts
inches
mm
versus drain pad area is shown in
6
Board Material = 0.0625″
G−10/FR−4, 2 oz Copper
2
PAK Package (Typical)
8
10
12
T
A
14
= 25°C
16