RT9193
For recommended operating conditions specification of
RT9193, where T
J(MAX)
is the maximum junction
temperature of the die (125°C) and T
A
is the maximum
ambient temperature. The junction to ambient thermal
resistance (θ
JA
is layout dependent) for TSOT-23-5/
SOT-23-5 package is 250°C/W, SC-70-5 package is 333°C/
W, WDFN-6L 2x2 package is 165°C/W and MSOP-8
package is 160°C/W on standard JEDEC 51-3 thermal
test board. The maximum power dissipation at T
A
= 25°C
can be calculated by following formula :
P
D(MAX)
= (125°C−25°C) / 333 = 300mW for SC-70-5
P
D(MAX)
= (125°C−25°C) / 250 = 400mW for TSOT-23-5/
SOT-23-5
P
D(MAX)
= (125°C−25°C) / 165 = 606mW for WDFN-6L 2x2
P
D(MAX)
= (125°C−25°C) / 160 = 625mW for MSOP-8
The maximum power dissipation depends on operating
ambient temperature for fixed T
J(MAX)
and thermal
resistance
θ
JA
. For RT9193 packages, the Figure 2 of
derating curves allows the designer to see the effect of
rising ambient temperature on the maximum power
allowed.
700
600
MSOP-8
WDFN-6L 2x2
Power Dissipation (mW)
500
400
300
200
100
0
0
TSOT-23-5/
SOT-23-5
SC 70-5
25
50
75
100
125
Ambient Temperature (°C)
Figure 2. Derating Curve for Packages
DS9193-11 May 2008
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