User manual
5 
TDK-Lambda 
LS 25-150 Series 
INSTRUCTION MANUAL 
5. Mounting Directions 
5-1. Output Derating according to the Mounting Directions 
Recommended standard mounting is Method ( A ). Method ( B ), ( C ) and ( D ) are also possible. Refer to the Output 
Derating below. Please do not use installation Method ( E ), where the PCB will be on the topside and heat will be 
trapped inside the unit. 
In the following derating curve, the maximum output current is denoted as 100%. 
` 
(A) Output Derating versus Ambient Temperature (Convection Cooling) 
LS25-3.3 
Output Derating Vs Ambient Temperature
0
20
40
60
80
100
120
-25 0 25 50 75 100
Ambient Temperature (
o
C)
Load (%) 
Mounting 
A & D 
Mounting 
B & C 
50 
 40   65  70 










