Ceramic transient voltage suppressors
SMD disk varistors for automotive applications
Series/Type:
Date: August 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.
EPCOS type designation system for SMD disk varistor automotive series
CU 4032 K 14 AUTO G2
Construction:
CU Encapsulated chip
Case sizes:
0225 32 x 25
4032 40 x 32
Varistor voltage tolerance:
K±10%
Maximum RMS operating voltage (VRMS):
14 14 V
17 17 V
30 30 V
Automotive series
Taping mode:
G2 Taped, 330-mm reel
SMD disk varistors (CU varistors)
Automotive series
Page 2 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Features
12 V and 24 V supply systems
High energy absorption capability
SMD plastic package
No temperature derating up to 85 °C
RoHS-compatible
Suitable for lead-free soldering
UL approved
PSpice simulation modeling available for different pulses
Applications
Load dump protection acc. to ISO 7637, pulse 5
Jump start protection
Design
Cylindrical varistor element, encapsulated.
Encapsulation: thermoplastic, flame-retardant to UL 94 V-0.
Termination: tinned copper alloy, suitable for lead-free wave and reflow soldering, and
compatible with tin/lead solder.
V/I characteristics and derating curves
V/I and derating curves are attached to the data sheet. The curves are sorted by VRMS and
then by case size, which is included in the type designation.
General technical data
Maximum RMS operating voltage VRMS,max 14 ... 30 V
Maximum DC operating voltage VDC,max 16 ... 34 V
Maximum surge current (8/20 µs) Isurge,max 100 ... 250 A
Maximum load dump energy (10 pulses) WLD 6 ... 12 J
Maximum jump start voltage (5 min) Vjump 25 ... 50 V
Maximum energy absorption (2 ms) Wmax 400 ... 2000 mJ
Maximum clamping voltage (8/20 µs) Vclamp,max 43 ... 93 V
Operating temperature Top 40/+85 °C
Storage temperature LCT/UCT 40/+125 °C
SMD disk varistors (CU varistors)
Automotive series
Page 3 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Temperature derating
Climatic category: 40/+85 °C
Electrical specifications and ordering codes
Maximum ratings (Top,max =85°C)
Type Ordering code VRMS,max
V
VDC,max
V
Isurge,max
(8/20 µs)
A
Wmax
(2 ms)
mJ
WLD
(10
pulses)
J
Pdiss,max
mW
CU3225K14AUTOG2 B72650M1140K072 14 16 100 400 6 10
CU4032K14AUTOG2 B72660M1140K072 14 16 250 900 12 20
CU3225K17AUTOG2 B72650M1170K072 17 20 100 500 6 10
CU4032K17AUTOG2 B72660M1170K072 17 20 250 1100 12 20
CU3225K30AUTOG2 B72650M1300K072 30 34 100 900 6 10
CU4032K30AUTOG2 B72660M1300K072 30 34 250 2000 12 20
Characteristics (TA=25°C)
Type VV
(1 mA)
V
∆VV
%
Vjump
(5 min)
V
Vclamp,max
V
Iclamp
(8/20 µs)
A
Ctyp
(1 kHz, 1 V)
pF
CU3225K14AUTOG2 22 ±10 25 43 1 1400
CU4032K14AUTOG2 22 ±10 25 43 2.5 2300
CU3225K17AUTOG2 27 ±10 30 53 1 1200
CU4032K17AUTOG2 27 ±10 30 53 2.5 1900
CU3225K30AUTOG2 47 ±10 50 93 1 600
CU4032K30AUTOG2 47 ±10 50 93 2.5 1100
SMD disk varistors (CU varistors)
Automotive series
Page 4 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Dimensional drawing
Dimensions in mm
Chip size
EIA in mm
VRMS,max l w h
3225 14, 17, 30 8.0 ±0.3 6.3 ±0.3 3.2 ±0.3
4032 14, 17, 30 10.2 ±0.3 8.0 ±0.3 3.2 ±0.3
Recommended solder pad layout
Dimensions in mm
Chip size
EIA in mm
ABC
3225 3.50 2.80 4.50
4032 3.50 2.80 6.50
Delivery mode
EIA case size Taping Reel size
mm
Packing unit
pcs.
Type Ordering code
3225 Blister 330 1000 CU3225K14AUTOG2 B72650M1140K072
3225 Blister 330 1000 CU3225K17AUTOG2 B72650M1170K072
3225 Blister 330 1000 CU3225K30AUTOG2 B72650M1300K072
4032 Blister 330 1000 CU4032K14AUTOG2 B72660M1140K072
4032 Blister 330 1000 CU4032K17AUTOG2 B72660M1170K072
4032 Blister 330 1000 CU4032K30AUTOG2 B72660M1300K072
SMD disk varistors (CU varistors)
Automotive series
Page 5 of 30Please read Cautions and warnings and
Important notes at the end of this document.
V/I characteristics
CU3225 ... AUTOG2
CU4032 ... AUTOG2
SMD disk varistors (CU varistors)
Automotive series
Page 6 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Derating curves
Maximum surge current Isurge,max = f (tr, pulse train)
For explanation of the derating curves refer to "General technical information", chapter 2.7.2
CU3225K14AUTOG2 ... K30AUTOG2
CU4032K14AUTOG2 ... K30AUTOG2
SMD disk varistors (CU varistors)
Automotive series
Page 7 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Taping and packing
1 Taping and packing for SMD components
1.1 Blister tape (the taping to IEC 60286-3)
Dimensions in mm
8-mm tape 12-mm tape 16-mm tape
Case size (inch/mm) Case size
(inch/mm)
Case size
(inch/mm)
Tolerance
0508/
1220
0612/
1632
1012/
2532
0603/
1608
0506/
1216
0805/
2012
1206/
3216
1210/
3225
1812/
4532
2220/
5750 3225 4032
A00.9 ±0.10 1.50 1.60 1.90 2.80 3.50 5.10 7.00 8.60 ±0.20
B01.75 ±0.10 1.80 2.40 3.50 3.50 4.80 6.00 8.70 10.60 ±0.20
K01.0 0.80 1.80 2.60 5.00 max.
T 0.30 0.30 0.30 max.
T21.3 1.20 2.50 3.50 5.50 max.
D01.50 1.50 1.50 +0.10/0
D11.00 1.50 1.50 min.
P04.00 4.00 4.00 ±0.101)
P22.00 2.00 2.00 ±0.05
P14.00 8.00 12.00 ±0.10
W 8.00 12.00 16.00 ±0.30
E 1.75 1.75 1.75 ±0.10
F 3.50 5.50 7.50 ±0.05
G 0.75 0.75 0.75 min.
1) ≤±0.2 mm over 10 sprocket holes.
SMD disk varistors (CU varistors)
Automotive series
Page 8 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Part orientation in tape pocket for blister tape
For discrete chip, case sizes 0603, 0805,
1206, 1210, 1812 and 2220
For array, case sizes 0612
For arrays 0506 and 1012 For filter array, case size 0508
Additional taping information
Reel material Polystyrol (PS)
Tape material Polystyrol (PS) or Polycarbonat (PC) or PVC
Tape break force min. 10 N
Top cover tape strength min. 10 N
Top cover tape peel force 0.2 to 0.6 N for 8-mm tape and 0.2 to 0.8 N for
12-mm tape at a peel speed of 300 mm/min
Tape peel angle Angle between top cover tape and the direction of feed
during peel off: 165°to 180°
Cavity play Each part rests in the cavity so that the angle between
the part and cavity center line is no more than 20°
SMD disk varistors (CU varistors)
Automotive series
Page 9 of 30Please read Cautions and warnings and
Important notes at the end of this document.
1.2 Cardboard tape (taping to IEC 60286-3)
Dimensions in mm
8-mm tape
Case size (inch/mm) Case size
(inch/mm) Tolerance
0201/0603 0402/1005 0405/1012 0603/1608 1003/2508 0508/1220
A00.38 ±0.05 0.60 1.05 0.95 1.00 1.60 ±0.20
B00.68 ±0.05 1.15 1.60 1.80 2.85 2.40 ±0.20
T 0.35 ±0.02 0.60 0.75 0.95 1.00 0.95 max.
T20.4 min. 0.70 0.90 1.10 1.10 1.12 max.
D01.50 ±0.1 1.50 1.50 +0.10/0
P04.00 ±0.102)
P22.00 ±0.05
P12.00 ±0.05 2.00 4.00 4.00 4.00 4.00 ±0.10
W 8.00 ±0.30
E 1.75 ±0.10
F 3.50 ±0.05
G 1.35 0.75 min.
2) ≤0.2 mm over 10 sprocket holes.
SMD disk varistors (CU varistors)
Automotive series
Page 10 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Part orientation in tape pocket for cardboard tape
For discrete chip case sizes 0201, 0402, 0603
and 1003
For array case size 0405
For array case size 0508 For filter array, case size 0405
Additional taping information
Reel material Polystyrol (PS)
Tape material Cardboard
Tape break force min. 10 N
Top cover tape strength min. 10 N
Top cover tape peel force 0.1 to 0.65 N at a peel speed of 300 mm/min
Tape peel angle Angle between top cover tape and the direction of feed
during peel off: 165°to 180°
Cavity play Each part rests in the cavity so that the angle between
the part and cavity center line is no more than 20°
SMD disk varistors (CU varistors)
Automotive series
Page 11 of 30Please read Cautions and warnings and
Important notes at the end of this document.
1.3 Reel packing
Dimensions in mm
8-mm tape 12-mm tape 16-mm tape
180-mm reel 330-mm reel 180-mm reel 330-mm reel 330-mm reel
A 180 3/+0 330 2.0 180 3/+0 330 2.0 330 2.0
W18.4 +1.5/0 8.4 +1.5/0 12.4 +1.5/0 12.4 +1.5/0 16.4 +1.5/0
W214.4 max. 14.4 max. 18.4 max. 18.4 max. 22.4 max.
Leader, trailer
SMD disk varistors (CU varistors)
Automotive series
Page 12 of 30Please read Cautions and warnings and
Important notes at the end of this document.
1.4 Packing units for discrete chip and array chip
Case size Chip thickness Cardboard tape Blister tape ∅180-mm reel ∅330-mm reel
inch/mm th W Wpcs. pcs.
0201/0603 0.33 mm 8 mm 15000
0402/1005 0.6 mm 8 mm 10000
0405/1012 0.7 mm 8 mm 5000
0506/1216 0.5 mm 8 mm 4000
0508/1220 0.9 mm 8 mm 8 mm 4000
0603/1608 0.9 mm 8 mm 8 mm 4000 16000
0612/1632 0.9 mm 8 mm 3000
0805/2012 0.7 mm 8 mm 3000
0.9 mm 8 mm 3000 12000
1.3 mm 8 mm 3000
1003/2508 0.9 mm 8 mm 4000
1012/2532 1.0 mm 8 mm 2000
1206/3216 0.9 mm 8 mm 3000
1.3 mm 8 mm 3000
1.4 mm 8 mm 2000
1.6 mm 8 mm 2000
1210/3225 0.9 mm 8 mm 3000
1.3 mm 8 mm 3000
1.4 mm 8 mm 2000
1.6 mm 8 mm 2000
1812/4532 1.3 mm 12 mm 1500
1.4 mm 12 mm 1000
1.6 mm 12 mm 4000
2.3 mm 12 mm 3000
2220/5750 1.3 mm 12 mm 1500
1.4 mm 12 mm 1000
2.0 mm 12 mm 3000
2.3 mm 12 mm 3000
3225 3.2 mm 16 mm 1000
4.5 mm 16 mm 1000
4032 3.2 mm 16 mm 1000
4.5 mm 16 mm 1000
SMD disk varistors (CU varistors)
Automotive series
Page 13 of 30Please read Cautions and warnings and
Important notes at the end of this document.
2 Delivery mode for leaded SHCV varistors
Standard delivery mode for SHCV types is bulk. Alternative taping modes (AMMO pack or taped
on reel) are available upon request.
Packing units for:
Type Pieces
SR6 2000
SR1 / SR2 1000
For types not listed in this data book please contact EPCOS.
SMD disk varistors (CU varistors)
Automotive series
Page 14 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Soldering directions
1 Terminations
1.1 Nickel barrier termination
The nickel barrier layer of the silver/nickel/tin termination prevents leaching of the silver base met-
allization layer. This allows great flexibility in the selection of soldering parameters. The tin pre-
vents the nickel layer from oxidizing and thus ensures better wetting by the solder. The nickel bar-
rier termination is suitable for all commonly-used soldering methods.
Multilayer CTVS: Structure of nickel barrier termination
1.2 Silver-palladium termination
Silver-palladium terminations are used for the large case sizes 1812 and 2220 and for chips in-
tended for conductive adhesion. This metallization improves the resistance of large chips to ther-
mal shock.
In case of conductive adhesion, the silver-palladium metallization reduces susceptibility to corro-
sion. Silver-palladium termination can be used for smaller case sizes (only chip) for hybrid appli-
cations as well. The silver-palladium termination is not approved for lead-free soldering.
Multilayer varistor: Structure of silver-palladium termination
SMD disk varistors (CU varistors)
Automotive series
Page 15 of 30Please read Cautions and warnings and
Important notes at the end of this document.
1.3 Silver-platinum termination
Silver-platinum terminations are mainly used for the large case sizes 1812 and 2220. The silver-
platinum termination is approved for reflow soldering, SnPb soldering and lead-free soldering with
a silver containing solder paste. In case of SnPb soldering, a solder paste Sn62Pb36Ag2 is rec-
ommended. For lead-free reflow soldering, a solder paste SAC, e.g. Sn95.5Ag3.8Cu0.7, is rec-
ommended.
Multilayer varistor: Structure of silver-platinum termination
2 Recommended soldering temperature profiles
2.1 Reflow soldering temperature profile
Recommended temperature characteristic for reflow soldering following
JEDEC J-STD-020D
SMD disk varistors (CU varistors)
Automotive series
Page 16 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Profile feature Sn-Pb eutectic assembly Pb-free assembly
Preheat and soak
- Temperature min Tsmin 100 °C 150 °C
- Temperature max Tsmax 150 °C 200 °C
- Time tsmin to tsmax 60 ... 120 s 60 ... 180 s
Average ramp-up rate Tsmax to Tp3°C/ s max. 3 °C/ s max.
Liquidous temperature TL183 °C 217 °C
Time at liquidous tL60 ... 150 s 60 ... 150 s
Peak package body temperature Tp1) 220 °C ... 235 °C2) 245 °C ... 260 °C2)
Time (tP)3) within 5 °C of specified
classification temperature (Tc)20 s3) 30 s3)
Average ramp-down rate Tpto Tsmax 6°C/ s max. 6 °C/ s max.
Time 25 °C to peak temperature maximum 6 min maximum 8 min
1) Tolerance for peak profile temperature (TP) is defined as a supplier minimum and a user maximum.
2) Depending on package thickness. For details please refer to JEDEC J-STD-020D.
3) Tolerance for time at peak profile temperature (tP) is defined as a supplier minimum and a user maximum.
Note: All temperatures refer to topside of the package, measured on the package body surface.
Number of reflow cycles: 3
2.2 Wave soldering temperature profile
Temperature characteristics at component terminal with dual-wave soldering
SMD disk varistors (CU varistors)
Automotive series
Page 17 of 30Please read Cautions and warnings and
Important notes at the end of this document.
2.3 Lead-free soldering processes
EPCOS multilayer CTVS with AgNiSn termination are designed for the requirements of lead-free
soldering processes only.
Soldering temperature profiles to JEDEC J-STD-020D, IEC 60068-2-58 and ZVEI recommenda-
tions.
3 Recommended soldering methods - type-specific releases by EPCOS
3.1 Overview
Reflow soldering Wave soldering
Type Case size SnPb Lead-free SnPb Lead-free
CT... / CD... 0201/ 0402 Approved Approved No No
CT... / CD... 0603 ... 2220 Approved Approved Approved Approved
CN... 0603 ... 2220 Approved No Approved No
CN...K2 1812, 2220 Approved Approved No No
Arrays 0405 ... 1012 Approved Approved No No
ESD/EMI filters 0405, 0508 Approved Approved No No
CU 3225, 4032 Approved Approved Approved Approved
SHCV - No No Approved Approved
3.2 Nickel barrier and AgPt terminated multilayer CTVS
All EPCOS MLVs with nickel barrier and AgPt termination are suitable and fully qualiyfied for lead-
free soldering. The nickel barrier layer is 100% matte tin-plated.
3.3 Silver-palladium terminated MLVs
AgPd-terminated MLVs are mainly designed for conductive adhesion technology on hybrid materi-
al. Additionally MLVs with AgPd termination are suitable for reflow and wave soldering with SnPb
solder.
Note:
Lead-free soldering is not approved for MLVs with AgPd termination.
3.4 Silver-platinum terminated MLVs
The silver-platinum termination is approved for reflow soldering, SnPb soldering and lead-free
with a silver containing solder paste. In case of SnPb soldering, a solder paste Sn62Pb36Ag2 is
recommended. For lead-free reflow soldering, a solder paste SAC, e.g. Sn95.5Ag3.8Cu0.7, is
recommended.
SMD disk varistors (CU varistors)
Automotive series
Page 18 of 30Please read Cautions and warnings and
Important notes at the end of this document.
3.5 Tinned copper alloy
All EPCOS CU types with tinned termination are approved for lead-free and SnPb soldering.
3.6 Tinned iron wire
All EPCOS SHCV types with tinned termination are approved for lead-free and SnPb soldering.
4 Solder joint profiles / solder quantity
4.1 Nickel barrier termination
If the meniscus height is too low, that means the solder quantity is too low, the solder joint may
break, i.e. the component becomes detached from the joint. This problem is sometimes interpret-
ed as leaching of the external terminations.
If the solder meniscus is too high, i.e. the solder quantity is too large, the vise effect may occur.
As the solder cools down, the solder contracts in the direction of the component. If there is too
much solder on the component, it has no leeway to evade the stress and may break, as in a vise.
The figures below show good and poor solder joints for dual-wave and infrared soldering.
4.1.1 Solder joint profiles for nickel barrier termination - dual-wave soldering
Good and poor solder joints caused by amount of solder in dual-wave soldering.
4.1.2 Solder joint profiles for nickel barrier termination / silver-palladium / silver-platinum
termination - reflow soldering
SMD disk varistors (CU varistors)
Automotive series
Page 19 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Good and poor solder joints caused by amount of solder in reflow soldering.
5 Conductive adhesion
Attaching surface-mounted devices (SMDs) with electrically conductive adhesives is a commer-
cially attractive method of component connection to supplement or even replace conventional sol-
dering methods.
Electrically conductive adhesives consist of a non-conductive plastic (epoxy resin, polyimide or
silicon) in which electrically conductive metal particles (gold, silver, palladium, nickel, etc) are em-
bedded. Electrical conduction is effected by contact between the metal particles.
Adhesion is particularly suitable for meeting the demands of hybrid technology. The adhesives
can be deposited ready for production requirements by screen printing, stamping or by dis-
pensers. As shown in the following table, conductive adhesion involves two work operations fewer
than soldering.
Reflow soldering Wave soldering Conductive adhesion
Screen-print solder paste Apply glue dot Screen-print conductive adhesive
Mount SMD Mount SMD Mount SMD
Predry solder paste Cure glue Cure adhesive
Reflow soldering Wave soldering Inspect
Wash Wash
Inspect Inspect
SMD disk varistors (CU varistors)
Automotive series
Page 20 of 30Please read Cautions and warnings and
Important notes at the end of this document.
A further advantage of adhesion is that the components are subjected to virtually no temperature
shock at all. The curing temperatures of the adhesives are between 120 °C and 180 °C, typical
curing times are between 30 minutes and one hour.
The bending strength of glued chips is, in comparison with that of soldered chips, higher by a fac-
tor of at least 2, as is to be expected due to the elasticity of the glued joints.
The lower conductivity of conductive adhesive may lead to higher contact resistance and thus re-
sult in electrical data different to those of soldered components. Users must pay special attention
to this in RF applications.
6 Solderability tests
Test Standard Test conditions
Sn-Pb soldering
Test conditions
Pb-free soldering
Criteria/ test results
Wettability IEC
60068-2-58
Immersion in
60/40 SnPb solder
using non-activated
flux at 215 ±3°C
for 3 ±0.3 s
Immersion in
Sn96.5Ag3.0Cu0.5
solder using non- or
low activated flux
at 245 ±5°C
for 3 ±0.3 s
Covering of 95% of
end termination,
checked by visual
inspection
Leaching
resistance
IEC
60068-2-58
Immersion in
60/40 SnPb
solder using
mildly activated flux
without preheating
at 260 ±5°C
for 10 ±1 s
Immersion in
Sn96.5Ag3.0Cu0.5
solder using non- or
low activated flux
without preheating
at 255 ±5°C
for 10 ±1 s
No leaching of
contacts
Thermal shock
(solder shock)
Dip soldering at
300 °C/5 s
Dip soldering at
300 °C/5 s
No deterioration of
electrical parameters.
Capacitance change:
≤ ±15%
Tests of resistance
to soldering heat
for SMDs
IEC
60068-2-58
Immersion in
60/40 SnPb for 10 s
at 260 °C
Immersion in
Sn96.5Ag3.0Cu0.5
for 10 s at 260 °C
Change of varistor
voltage:
≤ ±5%
Tests of resistance
to soldering heat
for radial leaded
components
(SHCV)
IEC
60068-2-20
Immersion
of leads in
60/40 SnPb
for 10 s at 260 °C
Immersion
of leads in
Sn96.5Ag3.0Cu0.5
for 10 s at 260 °C
Change of varistor
voltage: ≤ ±5%
Change of
capacitance X7R:
≤5/+10%
SMD disk varistors (CU varistors)
Automotive series
Page 21 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Note:
Leaching of the termination
Effective area at the termination might be lost if the soldering temperature and/or immersion time
are not kept within the recommended conditions. Leaching of the outer electrode should not ex-
ceed 25% of the chip end area (full length of the edge A-B-C-D) and 25% of the length A-B,
shown below as mounted on substrate.
As a single chip As mounted on substrate
7 Notes for proper soldering
7.1 Preheating and cooling
According to JEDEC J-STD-020D. Please refer to chapter 2.
7.2 Repair / rework
Manual soldering with a soldering iron must be avoided, hot-air methods are recommended for
rework purposes.
7.3 Cleaning
All environmentally compatible agents are suitable for cleaning. Select the appropriate cleaning
solution according to the type of flux used. The temperature difference between the components
and cleaning liquid must not be greater than 100 °C. Ultrasonic cleaning should be carried out
with the utmost caution. Too high ultrasonic power can impair the adhesive strength of the metal-
lized surfaces.
7.4 Solder paste printing (reflow soldering)
An excessive application of solder paste results in too high a solder fillet, thus making the chip
more susceptible to mechanical and thermal stress. Too little solder paste reduces the adhesive
strength on the outer electrodes and thus weakens the bonding to the PCB. The solder should be
applied smoothly to the end surface.
SMD disk varistors (CU varistors)
Automotive series
Page 22 of 30Please read Cautions and warnings and
Important notes at the end of this document.
7.5 Adhesive application
Thin or insufficient adhesive causes chips to loosen or become disconnected during curing.
Low viscosity of the adhesive causes chips to slip after mounting. It is advised to consult the
manufacturer of the adhesive on proper usage and amounts of adhesive to use.
7.6 Selection of flux
Used flux should have less than or equal to 0.1 wt % of halogenated content, since flux residue
after soldering could lead to corrosion of the termination and/or increased leakage current on the
surface of the component. Strong acidic flux must not be used. The amount of flux applied should
be carefully controlled, since an excess may generate flux gas, which in turn is detrimental to sol-
derability.
7.7 Storage of CTVSs
Solderability is guaranteed for one year from date of delivery for multilayer varistors, CeraDiodes
and ESD/EMI filters (half a year for chips with AgPd and AgPt terminations) and two years for
SHCV and CU components, provided that components are stored in their original packages.
Storage temperature: 25 °C to +45 °C
Relative humidity: ≤75% annual average, ≤95% on 30 days a year
The solderability of the external electrodes may deteriorate if SMDs and leaded components are
stored where they are exposed to high humidity, dust or harmful gas (hydrogen chloride, sulfurous
acid gas or hydrogen sulfide).
Do not store SMDs and leaded components where they are exposed to heat or direct sunlight.
Otherwise the packing material may be deformed or SMDs/ leaded components may stick togeth-
er, causing problems during mounting.
After opening the factory seals, such as polyvinyl-sealed packages, it is recommended to use the
SMDs or leaded components as soon as possible.
7.8 Placement of components on circuit board
Especially in the case of dual-wave soldering, it is of advantage to place the components on the
board before soldering in that way that their two terminals do not enter the solder bath at different
times.
Ideally, both terminals should be wetted simultaneously.
7.9 Soldering cautions
An excessively long soldering time or high soldering temperature results in leaching of the outer
electrodes, causing poor adhesion and a change of electrical properties of the varistor due to
the loss of contact between electrodes and termination.
Wave soldering must not be applied for MLVs designated for reflow soldering only.
Keep the recommended down-cooling rate.
SMD disk varistors (CU varistors)
Automotive series
Page 23 of 30Please read Cautions and warnings and
Important notes at the end of this document.
7.10 Standards
CECC 00802
IEC 60068-2-58
IEC 60068-2-20
JEDEC J-STD-020D
SMD disk varistors (CU varistors)
Automotive series
Page 24 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Symbols and terms
Symbol Term
Cline,typ Typical capacitance per line
Cmax Maximum capacitance
Cmin Minimum capacitance
Cnom Nominal capacitance
∆Cnom Tolerance of nominal capacitance
Ctyp Typical capacitance
fcut-off,min Minimum cut-off frequency
I Current
Iclamp Clamping current
Ileak Leakage current
Ileak,typ Typical leakage current
IPP Peak pulse current
Isurge,max Maximum surge current (also termed peak current)
LCT Lower category temperature
Ltyp Typical inductance
Pdiss,max Maximum power dissipation
PPP Peak pulse power
Rins Insulation resistance
Rmin Minimum resistance
RSResistance per line
TAAmbient temperature
Top Operating temperature
Tstg Storage temperature
trDuration of equivalent rectangular wave
tresp Response time
UCT Upper category temperature
V Voltage
VBR,min Minimum breakdown voltage
Vclamp,max Maximum clamping voltage
VDC,max Maximum DC operating voltage (also termed working voltage)
VESD,air Air discharge ESD capability
VESD,contact Contact discharge ESD capability
Vjump Maximum jump start voltage
SMD disk varistors (CU varistors)
Automotive series
Page 25 of 30Please read Cautions and warnings and
Important notes at the end of this document.
VRMS,max Maximum AC operating voltage, root-mean-square value
VVVaristor voltage (also termed breakdown voltage)
VV,min Minimum varistor voltage
VV,max Maximum varistor voltage
∆VVTolerance of varistor voltage
WLD Maximum load dump
Wmax Maximum energy absorption (also termed transient energy)
αtyp Typical insertion loss
Lead spacing
*Maximum possible application conditions
All dimensions are given in mm.
The commas used in numerical values denote decimal points.
SMD disk varistors (CU varistors)
Automotive series
Page 26 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Cautions and warnings
General
Some parts of this publication contain statements about the suitability of our ceramic transient
voltage suppressor (CTVS) components (multilayer varistors (MLVs), CeraDiodes, ESD/EMI
filters, SMD disk varistors (CU types), leaded transient voltage/ RFI suppressors (SHCV types))
for certain areas of application, including recommendations about incorporation/design-in of these
products into customer applications. The statements are based on our knowledge of typical
requirements often made of our CTVS devices in the particular areas. We nevertheless expressly
point out that such statements cannot be regarded as binding statements about the suitability of
our CTVS components for a particular customer application. As a rule, EPCOS is either unfamiliar
with individual customer applications or less familiar with them than the customers themselves.
For these reasons, it is always incumbent on the customer to check and decide whether the
CTVS devices with the properties described in the product specification are suitable for use in a
particular customer application.
Do not use EPCOS CTVS components for purposes not identified in our specifications,
application notes and data books.
Ensure the suitability of a CTVS in particular by testing it for reliability during design-in. Always
evaluate a CTVS component under worst-case conditions.
Pay special attention to the reliability of CTVS devices intended for use in safety-critical
applications (e.g. medical equipment, automotive, spacecraft, nuclear power plant).
Design notes
Always connect a CTVS in parallel with the electronic circuit to be protected.
Consider maximum rated power dissipation if a CTVS has insufficient time to cool down
between a number of pulses occurring within a specified isolated time period. Ensure that
electrical characteristics do not degrade.
Consider derating at higher operating temperatures. Choose the highest voltage class
compatible with derating at higher temperatures.
Surge currents beyond specified values will puncture a CTVS. In extreme cases a CTVS will
burst.
If steep surge current edges are to be expected, make sure your design is as low-inductance
as possible.
In some cases the malfunctioning of passive electronic components or failure before the end of
their service life cannot be completely ruled out in the current state of the art, even if they are
operated as specified. In applications requiring a very high level of operational safety and
especially when the malfunction or failure of a passive electronic component could endanger
human life or health (e.g. in accident prevention, life-saving systems, or automotive battery line
applications such as clamp 30), ensure by suitable design of the application or other measures
(e.g. installation of protective circuitry or redundancy) that no injury or damage is sustained by
third parties in the event of such a malfunction or failure. Only use CTVS components from the
automotive series in safety-relevant applications.
SMD disk varistors (CU varistors)
Automotive series
Page 27 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Specified values only apply to CTVS components that have not been subject to prior electrical,
mechanical or thermal damage. The use of CTVS devices in line-to-ground applications is
therefore not advisable, and it is only allowed together with safety countermeasures like
thermal fuses.
Storage
Only store CTVS in their original packaging. Do not open the package before storage.
Storage conditions in original packaging: temperature 25 to +45°C, relative humidity ≤75%
annual average, maximum 95%, dew precipitation is inadmissible.
Do not store CTVS devices where they are exposed to heat or direct sunlight. Otherwise the
packaging material may be deformed or CTVS may stick together, causing problems during
mounting.
Avoid contamination of the CTVS surface during storage, handling and processing.
Avoid storing CTVS devices in harmful environments where they are exposed to corrosive
gases for example (SOx, Cl).
Use CTVS as soon as possible after opening factory seals such as polyvinyl-sealed packages.
Solder CTVS components after shipment from EPCOS within the time specified:
CTVS with Ni barrier termination, 12 months
CTVS with AgPd and AgPt termination, 6 months
SHCV and CU series, 24 months
Handling
Do not drop CTVS components and allow them to be chipped.
Do not touch CTVS with your bare hands - gloves are recommended.
Avoid contamination of the CTVS surface during handling.
Mounting
When CTVS devices are encapsulated with sealing material or overmolded with plastic
material, electrical characteristics might be degraded and the life time reduced.
Make sure an electrode is not scratched before, during or after the mounting process.
Make sure contacts and housings used for assembly with CTVS components are clean before
mounting.
The surface temperature of an operating CTVS can be higher. Ensure that adjacent
components are placed at a sufficient distance from a CTVS to allow proper cooling.
Avoid contamination of the CTVS surface during processing.
Multilayer varistors (MLVs) with AgPd termination are not approved for lead-free soldering.
Soldering
Complete removal of flux is recommended to avoid surface contamination that can result in an
instable and/or high leakage current.
Use resin-type or non-activated flux.
Bear in mind that insufficient preheating may cause ceramic cracks.
Rapid cooling by dipping in solvent is not recommended, otherwise a component may crack.
SMD disk varistors (CU varistors)
Automotive series
Page 28 of 30Please read Cautions and warnings and
Important notes at the end of this document.
Conductive adhesive gluing
Only multilayer varistors (MLVs) with an AgPd termination are approved for conductive
adhesive gluing.
Operation
Use CTVS only within the specified operating temperature range.
Use CTVS only within specified voltage and current ranges.
Environmental conditions must not harm a CTVS. Only use them in normal atmospheric
conditions. Reducing the atmosphere (e.g. hydrogen or nitrogen atmosphere) is prohibited.
Prevent a CTVS from contacting liquids and solvents. Make sure that no water enters a CTVS
(e.g. through plug terminals).
Avoid dewing and condensation.
EPCOS CTVS components are mainly designed for encased applications. Under all
circumstances avoid exposure to:
direct sunlight
rain or condensation
steam, saline spray
corrosive gases
atmosphere with reduced oxygen content
EPCOS CTVS devices are not suitable for switching applications or voltage stabilization where
static power dissipation is required.
Multilayer varistors (MLVs) are designed for ESD protection and transient suppression.
CeraDiodes are designed for ESD protection only, ESD/EMI filters are designed for ESD and
EMI protection only.
This listing does not claim to be complete, but merely reflects the experience of EPCOS AG.
SMD disk varistors (CU varistors)
Automotive series
Page 29 of 30Please read Cautions and warnings and
Important notes at the end of this document.
The following applies to all products named in this publication:
1. Some parts of this publication contain statements about the suitability of our products for
certain areas of application. These statements are based on our knowledge of typical re-
quirements that are often placed on our products in the areas of application concerned. We
nevertheless expressly point out that such statements cannot be regarded as binding
statements about the suitability of our products for a particular customer application.
As a rule, EPCOS is either unfamiliar with individual customer applications or less familiar
with them than the customers themselves. For these reasons, it is always ultimately incum-
bent on the customer to check and decide whether an EPCOS product with the properties de-
scribed in the product specification is suitable for use in a particular customer application.
2. We also point out that in individual cases, a malfunction of electronic components or
failure before the end of their usual service life cannot be completely ruled out in the
current state of the art, even if they are operated as specified. In customer applications
requiring a very high level of operational safety and especially in customer applications in
which the malfunction or failure of an electronic component could endanger human life or
health (e.g. in accident prevention or lifesaving systems), it must therefore be ensured by
means of suitable design of the customer application or other action taken by the customer
(e.g. installation of protective circuitry or redundancy) that no injury or damage is sustained by
third parties in the event of malfunction or failure of an electronic component.
3. The warnings, cautions and product-specific notes must be observed.
4. In order to satisfy certain technical requirements, some of the products described in this
publication may contain substances subject to restrictions in certain jurisdictions (e.g.
because they are classed as hazardous). Useful information on this will be found in our Ma-
terial Data Sheets on the Internet (www.epcos.com/material). Should you have any more de-
tailed questions, please contact our sales offices.
5. We constantly strive to improve our products. Consequently, the products described in this
publication may change from time to time. The same is true of the corresponding product
specifications. Please check therefore to what extent product descriptions and specifications
contained in this publication are still applicable before or when you place an order. We also
reserve the right to discontinue production and delivery of products. Consequently, we
cannot guarantee that all products named in this publication will always be available. The
aforementioned does not apply in the case of individual agreements deviating from the fore-
going for customer-specific products.
6. Unless otherwise agreed in individual contracts, all orders are subject to the current ver-
sion of the "General Terms of Delivery for Products and Services in the Electrical In-
dustry" published by the German Electrical and Electronics Industry Association
(ZVEI).
7. The trade names EPCOS, BAOKE, Alu-X, CeraDiode, CSMP, CSSP, CTVS, DeltaCap,
DigiSiMic, DSSP, FormFit, MiniBlue, MiniCell, MKK, MKD, MLSC, MotorCap, PCC,
PhaseCap, PhaseCube, PhaseMod, PhiCap, SIFERRIT, SIFI, SIKOREL, SilverCap,
SIMDAD, SiMic, SIMID, SineFormer, SIOV, SIP5D, SIP5K, ThermoFuse, WindCap are trade-
marks registered or pending in Europe and in other countries. Further information will be
found on the Internet at www.epcos.com/trademarks.
Important notes
Page 30 of 30
