MUSES8820
- 4 -
Ver.2012-05-14
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■ Application Notes
•
Package Power, Power Dissipation and Output Power
IC is heated by own operation and possibly gets damage when the junction power exceeds the acceptable value called
Power Dissipation P
D
. The dependence of the MUSES8820 P
D
on ambient temperature is shown in Fig 1. The plots are
depended on following two points. The first is P
D
on ambient temperature 25°C, which is the maximum power dissipation.
The second is 0W, which means that the IC cannot radiate any more. Conforming the maximum junction temperature
Tjmax to the storage temperature Tstg derives this point. Fig.1 is drawn by connecting those points and conforming the P
D
lower than 25°C to it on 25°C. The P
D
is shown following formula as a function of the ambient temperature between those
points.
Dissipation Power [W] (Ta=25°C to Ta=150°C)
Where, θja is heat thermal resistance which depends on parameters such as package material, frame material and so on.
Therefore, P
D
is different in each package.
While, the actual measurement of dissipation power on MUSES8820 is obtained using following equation.
(Actual Dissipation Power) = (Supply Voltage V
DD
) X (Supply Current I
DD
) – (Output Power Po)
The MUSES8820 should be operated in lower than P
D
of the actual dissipation power.
To sustain the steady state operation, take account of the Dissipation Power and thermal design.
P
D
[mW]
Ta [deg]
-40 25
85
(Topr max.)
150
(Tstg max.)
900
EMP8
Fi
.1 Power Dissi
ations vs. Ambient Tem
erature on the MUSES8820
870
DIP8
Tjmax - Ta
θ
ja
P
D
=
