Datasheet

MCP1825/MCP1825S
DS22056B-page 22 © 2008 Microchip Technology Inc.
5.3.1.2 Junction Temperature Estimate
To estimate the internal junction temperature, the
calculated temperature rise is added to the ambient or
offset temperature. For this example, the worst-case
junction temperature is estimated below:
5.3.1.3 Maximum Package Power
Dissipation at 60°C Ambient
Temperature
From this table, you can see the difference in maximum
allowable power dissipation between the TO-220-5
package and the DDPAK-5 package.
T
J
=T
JRISE
+ T
A(MAX)
T
J
= 15.06°C + 60.0°C
T
J
= 75.06°C
TO-220-5 (29.3°C/W Rθ
JA
):
P
D(MAX)
= (125°C – 60°C) / 29.3°C/W
P
D(MAX)
= 2.218W
DDPAK-5 (31.2°C/Watt Rθ
JA
):
P
D(MAX)
= (125°C – 60°C)/ 31.2°C/W
P
D(MAX)
= 2.083W