Application notes
The following two important aspects for determining the right NTC inrush current limiter are
excerpted from the chapter "Application notes" in the "NTC Inrush Current Limiters,
Data book 2012". The complete application note can be downloaded from
www.epcos.com/ntcicl_appnotes.
1.4 Load derating
The power handling capability of an NTC thermistor cannot be fully utilized over the entire temper-
ature range. For circuit dimensioning the derating curve given below provides information on the
extent to which the current must be reduced at a certain ambient temperature (T
A
).
Derating curve for types S237, P11 and P13
Figure 1
T
A
= Ambient temperature > 25 °C
T
max
= 170 °C
Derating curve for types S153, S235, S236, S238, S364 and S464
Figure 2
Inrush current limiters B57127P0***M301
ICLs P27
Page 6 of 19Please read Cautions and warnings and
Important notes at the end of this document.
