NTC thermistors for

inrush current limiting

Leaded and coated disks

Series/Type: B57464S0***M000

Date: October 2011

© EPCOS AG 2011. Reproduction, publication and dissemination of this publication, enclosures hereto and the

information contained therein without EPCOS' prior express consent is prohibited.

1) For details on the capacitance Ctest as well as on the parameters k and n refer to "Application notes", chapters 1.6 and 1.7.

Kinked leads of tinned copper wire

High energy absorption capability

Resistance tolerance <20%, alternative lead

configurations and resistance ratings available on

Delivery mode

Dimensional drawing

Dimensions in mm

Approx. weight 9 g

Thermal cooling time constant (in air) τcapprox. 130 s

Heat capacity Cth approx. 3900 mJ/K

Electrical specification and ordering codes

R25

Imax

(0...65 °C)

B25/100

Ctest1)

230 V AC

µF

Ctest1)

110 V AC

µF

for R(I)1)

for R(I)1)

Reliability data

Storage in

dry heat

Storage at upper

category temperature

T: 170 °C

t: 1000 h

Storage in damp

heat, steady state

Temperature of air: 40 °C

Relative humidity of air: 93%

Duration: 21 days

Rapid temperature

Lower test temperature: 55 °C

Upper test temperature: 170 °C

Number of cycles: 10

Number of cycles: 1000

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.

Taping and packing

Dimensions (mm)

5 mm

lead spacing

5 mm

7.5 mm

lead spacing

7.5 mm

th 6.0 max. 7 max. please refer to dimensional

d 0.5/0.6 ±0.05 0.8/1.0 ±0.05 please refer to dimensional

P012.7 ±0.3 12.7 ±0.3 ±1 mm / 20 sprocket holes

P13.85 ±0.7 8.95 ±0.8

H 18.0 +2.0/0 18.0 +2.0/0

L 11.0 max. 11.0 max.

L14.0 max. 4.0 max.

Types of packing

Reel packing

Mounting instructions

1.1 Leaded NTC thermistors

Leaded thermistors comply with the solderability requirements specified by CECC.

to be observed:

Bath temperature max. 260 °C max. 360 °C

Soldering time max. 4 s max. 2 s

Distance from thermistor min. 6 mm min. 6 mm

Under more severe soldering conditions the resistance may change.

Preconditioning: Immersion into flux F-SW 32.

Solder Bath temperature (°C) Dwell time (s)

SnAg (3.0 ... 4.0), Cu (0.5 ... 0.9) 260 5 10

Wave soldering

Temperature characteristic at component terminal with dual wave soldering

2 Robustness of terminations

throughs. During bending, any mechanical stress at the outlet of the leads must be removed. The

bending radius should be at least 0.75 mm.

Tensile strength: Test Ua1:

When subjecting leads to mechanical stress, the following should be observed:

Tensile stress on leads

During mounting and operation tensile forces on the leads are to be avoided.

Bending of leads

Bending of the leads directly on the thermistor body is not permissible.

A lead may be bent at a minimum distance of twice the wire's diameter +2 mm from the solder

joint on the thermistor body. During bending the wire must be mechanically relieved at its outlet.

The bending radius should be at least 0.75 mm.

Twisting of leads

The twisting (torsion) by 180°of a lead bent by 90°is permissible at 6 mm from the bottom of the

thermistor body.