91930 Datasheet, PDF (3/6 Pages) EPCOS – NTC thermistors for inrush current limiting

Inrush current limiters
ICLs
B57237
S237
Reliability data
Test
Standard Test conditions
Storage in
dry heat
Storage in damp
heat, steady state
Rapid temperature
cycling
Endurance
Cyclic
endurance
Transient
load
IEC
60068-2-2
IEC
60068-2-78
IEC
60068-2-14
Storage at upper
category temperature
T: 170 °C
t: 1000 h
Temperature of air: 40 °C
Relative humidity of air: 93%
Duration: 21 days
Lower test temperature: 55 °C
Upper test temperature: 170 °C
Number of cycles: 10
I = I_max
t: 1000 h
I = I_max, 1000 cycles
On-time = 1 min
Cooling time = 6 min
Capacitance = C_test
Number of cycles: 1000
∆R₂₅/R₂₅
(typical)
< 10%
< 5%
< 10%
< 10%
< 10%
< 5%
Remarks
No visible
damage
No visible
damage
No visible
damage
No visible
damage
No visible
damage
No visible
damage
Cautions and warnings for ICLs
The self-heating of a thermistor during operation depends on the load applied and the applicable
dissipation factor.
When loaded with maximum allowable current/power and the specified dissipation factor is taken
as a basis, the NTC thermistor may reach a mean temperature of up to 250 °C.
The heat developed during operation will also be dissipated through the lead wires. So the
contact areas, too, may become quite hot at maximum load.
When mounting NTC thermistors you have to ensure that there is an adequate distance between
the thermistor and all parts which are sensitive to heat or combustible.
Please read Important notes and
Cautions and warnings at the end of this document.
Page 3 of 6