PTC thermistors for overcurrent
protection in telecom applications
Leadless round disks
Series/Type:
Date:
November 2009
© EPCOS AG 2009. Reproduction, publication and dissemination of this publication, enclosures hereto and the
information contained therein without EPCOS' prior express consent is prohibited.
Overcurrent protection for telecom
Leadless round disks
Applications
Overcurrent protection for telecom applications
Suitable for MDF applications e.g. connectors etc.
Features
Designed for combined usage of PTC and primary protection
(e.g. gas arrester)
Suitable for continuous connection to mains voltages
of 110/230 V AC in tripped (high-ohmic) condition
Matching available with narrow resistance tolerance
Tight resistance matching maintained after switching
Negligible resistance drift after soldering or switching
RoHS-compatible
Options
Alternative tolerances and resistances on request
Delivery mode
Packed in blister trays
General electrical data
Max. operating voltage
Operating temperature range
Operating temperature range
V
max
T
op
T
op
245
20/+125
0/+70
V AC
°C
°C
(V = 0)
(V = 230 V)
Electrical specifications and ordering codes
1)
Type
R
R
∆R
R
R
25,match
(per packing unit)
R
1
R
2 max
%
Ω
I
R
@
25°C
mA
I
R
@
70°C
mA
I
S
@
25°C
mA
I
Smax
@
230 V AC
A
t
S
(typ.) Ordering code
@ I
Smax,
230 V AC
s
4
12
2.0
2.0
4.0
0.2
1.15
B59093A0080B110
B59095A0080B110
B59037A1120B010
B59037A1120B110
B59042A1120B110
B59041A1120B110
B59044A1120B110
Ω
Round disks, contacts for clamp connection
A93
4.75
±15
0.9
160 70 370 1.0
A95
9.3
±10
0.4
110 50 250 0.5
Round disks, contacts for solder connection
A1037 10
±15
No
140 95 300 1.0
A1037 10
±15
1.0
140 95 300 1.0
A1042 10
±15
1.0
150 100 300 1.0
A1041 25
±15
1.0
100 65 200 2.8
A1044 35
±15
1.0
90 55 180 2.8
1) Variation of current and switching time with heat dissipation of mounting assembly must be taken into account.
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 2 of 8
Overcurrent protection for telecom
Leadless round disks
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: 10
Storage at V
max
/T
op
Test duration: 1000 h
Temperature of air: 40
°C
Relative humidity of air: 93%
Duration: 56 days
Test according to IEC 60068-2-78
∆R
25
/R
25
< 20%
< 25%
< 10%
Dimensional drawing
Dimensions in mm
Type
∅d
max
Round disks
A1037
6.6
A1041
8.1
A1042
8.1
A1044
8.1
A93
7.9
A95
7.8
th
max
1.7
2.1
2.1
2.1
2.1
2.6
Contacts
for solder connection
for solder connection
for solder connection
for solder connection
for clamp connection
for clamp connection
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 3 of 8
Overcurrent protection for telecom
Leadless round disks
Cautions and warnings
General
EPCOS thermistors are designed for specific applications and should not be used for purposes
not identified in our specifications, application notes and data books unless otherwise agreed
with EPCOS during the design-in-phase.
Ensure suitability of thermistor through reliability testing during the design-in phase. The ther-
mistors should be evaluated taking into consideration worst-case conditions.
Storage
Store thermistors only in original packaging. Do not open the package before storage.
Storage conditions in original packaging: storage temperature 25
°C
... +45
°C,
relative hu-
midity
≤75%
annual mean, maximum 95%, dew precipitation is inadmissible.
Avoid contamination of thermistors surface during storage, handling and processing.
Avoid storage of thermistor in harmful environment with effect on function on long-term opera-
tion (examples given under operation precautions).
Use thermistor within the following period after delivery:
Through-hole devices (housed and leaded PTCs): 24 months
Motor protection sensors, glass-encapsulated sensors and probe assemblies: 24 months
Telecom pair and quattro protectors (TPP, TQP): 24 months
Leadless PTC thermistors for pressure contacting: 12 months
Leadless PTC thermistors for soldering: 6 months
SMDs in EIA sizes 3225 and 4032, and for PTCs with metal tags: 24 months
SMDs in EIA sizes 0402, 0603, 0805 and 1210: 12 months
Handling
PTCs must not be dropped. Chip-offs must not be caused during handling of PTCs.
Components must not be touched with bare hands. Gloves are recommended.
Avoid contamination of thermistor surface during handling.
Soldering (where applicable)
Use rosin-type flux or non-activated flux.
Insufficient preheating may cause ceramic cracks.
Rapid cooling by dipping in solvent is not recommended.
Complete removal of flux is recommended.
Standard PTC heaters are not suitable for soldering.
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 4 of 8
Overcurrent protection for telecom
Leadless round disks
Mounting
Electrode must not be scratched before/during/after the mounting process.
Contacts and housing used for assembly with thermistor have to be clean before mounting. Es-
pecially grease or oil must be removed.
When PTC thermistors are encapsulated with sealing material, the precautions given in chapter
"Mounting instructions", "Sealing and potting" must be observed.
When the thermistor is mounted, there must not be any foreign body between the electrode of
the thermistor and the clamping contact.
The minimum force of the clamping contacts pressing against the PTC must be 10 N.
During operation, the thermistor’s surface temperature can be very high. Ensure that adjacent
components are placed at a sufficient distance from the thermistor to allow for proper cooling at
the thermistors.
Ensure that adjacent materials are designed for operation at temperatures comparable to the
surface temperature of thermistor. Be sure that surrounding parts and materials can withstand
this temperature.
Avoid contamination of thermistor surface during processing.
Operation
Use thermistors only within the specified temperature operating range.
Use thermistors only within the specified voltage and current ranges.
Environmental conditions must not harm the thermistors. Use thermistors only in normal at-
mospheric conditions. Avoid use in deoxidizing gases (chlorine gas, hydrogen sulfide gas, am-
monia gas, sulfuric acid gas etc), corrosive agents, humid or salty conditions. Contact with any
liquids and solvents should be prevented.
Be sure to provide an appropriate fail-safe function to prevent secondary product damage
caused by abnormal function (e.g. use VDR for limitation of overvoltage condition).
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 5 of 8
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