PTC thermistors for
overcurrent protection
Leaded disks, coated, 12 V, 24 V
Series/Type:
Date:
B599*5
June 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.
Overcurrent protection
Leaded disks, coated, 12 V, 24 V
C935 ... C995
Applications
Overcurrent protection
Short circuit protection
Features
Lead-free terminals
Manufacturer's logo and type designation
stamped on in white
Low resistance
For rated currents of up to 1.8 A
UL approval to UL 1434 for V
max
= 15 V and
V
R
= 12 V (file number E69802)
RoHS-compatible
Options
Leadless disks and leaded disks without
coating available on request
Thermistors with diameter w
≤11.0
mm are
also available on tape (to IEC 60286-2)
Delivery mode
Cardboard strips (standard)
Cardboard tape reeled or in Ammo pack on
request
General technical data
Max. operating voltage
Rated voltage
Switching cycles
Reference temperature
Tolerance of R
R
Operating temperature range
Operating temperature range
(T
A
= 60
°C)
Dimensional drawing
Dimensions (mm)
Type
C935
C945
C955
C965
C975
C985
C995
w
max
22.0
17.5
13.5
11.0
9.0
6.5
4.0
h
max
25.5
21.0
17.0
14.5
12.5
10.0
7.5
∅d
0.6
0.6
0.6
0.6
0.6
0.6
0.5
(typ.)
(V = 0)
(V = V
max
)
V
max
V
R
N
T
ref
∆R
R
T
op
T
op
30
12, 24
100
120
±25
40/+125
40/+85
V DC or V AC
V DC or V AC
°C
%
°C
°C
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 2 of 10
Overcurrent protection
Leaded disks, coated, 12 V, 24 V
C935 ... C995
Electrical specifications and ordering codes
Type
I
R
I
S
I
Smax
(V = V
max
)
A
I
r
(typ.)
(V = V
max
)
mA
170
115
80
70
60
45
25
R
R
R
min
Approvals Ordering code
mA
C935
C945
C955
C965
C975
C985
C995
1800
1300
850
600
450
250
120
mA
Ω
0.3
0.45
0.8
1.2
1.8
4.6
13
Ω
0.2
0.3
0.5
0.7
1.1
2.7
7.8
X
X
X
X
X
X
X
B59935C0120A070
B59945C0120A070
B59955C0120A070
B59965C0120A070
B59975C0120A070
B59985C0120A070
B59995C0120A070
3600 10.0
2600 8.0
1700 5.5
1200 4.3
900 3.0
500 1.0
240 0.7
Reliability data
Test
Electrical endurance,
cycling
Electrical endurance,
constant
Damp heat
Standard
IEC 60738-1
IEC 60738-1
IEC 60738-1
Test conditions
Room temperature, I
Smax
; V
max
Number of cycles: 100
Storage at V
max
/T
op,max
(V
max
)
Test duration: 1000 h
Temperature of air: 40
°C
Relative humidity of air: 93%
Duration: 56 days
Test according to IEC 60068-2-78
T
1
= T
op,min
(0 V), T
2
= T
op,max
(0 V)
Number of cycles: 5
Test duration: 30 min
Test according to IEC 60068-2-14, Test Na
Frequency range: 10 to 55 Hz
Displacement amplitude: 0.75 mm
Test duration: 3
×
2 h
Test according to IEC 60068-2-6, Test Fc
Acceleration: 390 m/s
2
Pulse duration: 6 ms; 6
×
4000 pulses
Dry heat: T = T
op,max
(0 V)
Test duration: 16 h
Damp heat first cycle
Cold: T = T
op,min
(0 V)
Test duration: 2 h
Damp heat 5 cycles
Tests performed according to
IEC 60068-2-30
∆R
25
/R
25
< 25%
< 25%
< 10%
Rapid change
of temperature
IEC 60738-1
< 10%
Vibration
IEC 60738-1
< 5%
Shock
Climatic sequence
IEC 60738-1
IEC 60738-1
< 5%
< 10%
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 3 of 10
Overcurrent protection
Leaded disks, coated, 12 V, 24 V
C935 ... C995
Characteristics (typical)
PTC resistance R
PTC
versus
PTC temperature T
PTC
(measured at low signal voltage)
PTC current I
PTC
versus PTC voltage V
PTC
(measured at 25
°C
in still air)
Switching time t
S
versus switching current I
S
(measured at 25
°C
in still air)
Rated current I
R
versus ambient temperature T
A
(measured in still air)
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 4 of 10
Overcurrent protection
Leaded disks, coated, 12 V, 24 V
C935 ... C995
Characteristics (typical)
PTC resistance R
PTC
versus
PTC temperature T
PTC
(measured at low signal voltage)
PTC current I
PTC
versus PTC voltage V
PTC
(measured at 25
°C
in still air)
Switching time t
S
versus switching current I
S
(measured at 25
°C
in still air)
Rated current I
R
versus ambient temperature T
A
(measured in still air)
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 5 of 10
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