Metal-Oxide Varistors (MOVs)
Surface Mount Multilayer Varistors (MLVs) > AUML Series
AUML Varistor Series
RoHS
Description
The AUML Series of Multilayer Transient Surge Suppressors
was specifically designed to suppress the destructive
transient voltages found in an automobile. The most common
transient condition results from large inductive energy
discharges. The electronic systems in the automobile, e.g.
antilock brake systems, direct ignition systems, engine
control, airbag control systems, wiper motor controls, etc.,
are susceptible to damage from these voltage transients and
thus require protection. The AUML transient suppressors
have temperature independent suppression characteristics
affording protection from -40ºC to 125ºC.
Size Table
Metric
EIA
3216
1206
3225
1210
4532
1812
5650
2220
The AUML suppressor is manufactured from semiconducting
ceramics which offer rugged protection and excellent
transient energy absorption in a small package. The devices
are available in ceramic leadless chip form, eliminating lead
inductance and assuring fast speed of response to transient
surges. These Suppressors require significantly smaller
space and land pads than Silicon TVS diodes, offering greater
circuit board layout flexibility for the designer.
Also see the Littelfuse ML, MLN and MLE Series of
Multilayer Suppressors.
Features
Applications
• Suppression of
inductive switching
or other transient
events such as EFT
and surge voltage at
the circuit board level
• ESD protection for
components sensitive
to IEC 61000-4-2
(Level 4), MIL-STD883C, Method 3015.7,
and other industry
specifications (See
Also the MLE or
MLN Series)
• Provides on-board
transient voltage
protection for ICs
and transistors
• RoHS Compliant
• Used to help achieve
electromagnetic
compliance of
end products
• Leadless, surface
mount chip form
• Replace larger surface
mount TVS Zeners in
many applications
• High peak surge
current capability
• AEC - Q200 compliant
• Low Profile, compact
industry standard chip
size; (1206, 1210, 1812
and 2220 Sizes)
• Load Dump energy
rated per SAE
Specification J1113
• “Zero” Lead Inductance
• Inherent bidirectional
clamping
• No Plastic or epoxy
packaging assures
better than 94V-0
• No temperature derating
flammability rating
up to 125ºC ambient
• Variety of energy
ratings available
Absolute Maximum Ratings
• For ratings of individual members of a series, see Device Ratings and Specifications chart.
Continuous
AUML Series
Units
18, 24, 48, 68
V
Steady State Applied Voltage
DC Voltage Range (VM(DC))
Transient
Load Dump Energy, (WLD)
Jump Start Capability (5 minutes), (VJUMP)
1.5 to 25
J
48
V
Operating Ambient Temperature Range (TA)
-40 to +125
O
Storage Temperature Range (TSTG)
-40 to +150
O
Temperature Coefficient (αV) of Clamping Voltage (VC) at Specified Test Current
AUML Series
Device Ratings and Specifications
Maximum Ratings (125ºC)
Part Number
Specifications (25ºC)
Maximum
Continuous DC
Voltage
Jump Start
Voltage
(5 Min)
Load Dump
Energy
(10 Pulses)
Nominal Varistor Voltage
at 10mA
DC Test Current
Maximum Standby
Leakage
(at 13V DC)
Maximum Clamping
Voltage (VC) at
Test Current (8/20µs)
VM(DC)
VJUMP
WLD
VN(DC) Min
VN(DC) Max
IL
VC
IP
(V)
(V)
(J)
(V)
(V)
(µA)
(V)
(A)
V18AUMLA1206
18
24.5
1.5
23
32
50
40
1.5
V18AUMLA1210
18
24.5
3.0
23
32
50
40
1.5
V18AUMLA1812
18
24.5
6.0
23
32
100
40
5.0
V18AUMLA2220
18
24.5
25
23
32
200
40
10.0
V24AUMLA2220
24
24.5
25
32
39
200
60
10.0
V48AUMLA2220
48
24.5
25
54.5
66.5
200
105
10.0
V68AUMLA2220
68
24.5
25
77.2
94.4
200
135
10.0
NOTES: 1. Average power dissipation of transients not to exceed 0.1W, 0.15W, 0.3W and 1W for model sizes 1206, 1210, 1812 and 2220 respectively.
2. Load dump :min. time of energy input 40ms, interval 60sec(the load dump time constant Td differs from the time constant of energy input; load dump rating for ISO 7637-2 pulse
5a, please contact littelfuse.
3. Thermal shock capability per Mil-Std-750, Method 1051: -55ºC to 125ºC, 5 minutes at 25ºC, 25 Cycles: 15 minutes at each extreme.
4. For application specific requirements, please contact Littelfuse.
Current, Energy and Power Derating Curve
Peak Pulse Current Test Waveform for Clamping Voltage
100
90
PERCENT OF RATED VALUE
100
PERCENT OF PEAK VALUE
When transients occur in rapid succession, the average
power dissipation is the energy (watt-seconds) per pulse
times the number of pulses per second. The power so
developed must be within the specifications shown on the
Device Ratings and Characteristics Table for the specific
device. Certain parameter ratings must be derated at high
temperatures as shown below.
50
0
T
O1
80
TIME
T1
MAXIMUM LEAKAGE
70
100
Figure
2
60
50
40
VOLTAGE
30
20
10
0
-55
50
60
70
80
90
100 110
120
130
140 150
AMBIENT TEMPERATURE (oC)
Figure 1
10
for
AUML Series at 25ºC
1210/1206
1812
2220
01 = Virtual Origin of Wave
T = Time from 10% to 90% of Peak
1210/1206
T1 = Rise
Time = 1.25 x T
FIGURE
2. PEAK PULSE CURRENT TEST WAVEFORM
1812
T2220
=
Decay
Time
FOR
CLAMPING VOLTAGE
2
Example - For an 8/20 µs Current Waveform:
O1 = VIRTUAL
ORIGIN
OF WAVE
8µs = T
= Rise
Time
1
t = TIME
FROM
90% OF
PEAK
20µs
= T10%
= TO
Decay
Time
2
t1 = VIRTUAL FRONT TIME = 1.25 x t
1mA
10µA
100µA
1A
10A
VIRTUAL
TIME TO
HALF10mA
VALUE 100mA
t2 =
CURRENT
DURATION)of the V18AUMLA2220
Typical V-I(IMPULSE
Characteristics
1
FIGURE 1. CURRENT, ENERGY AND POWER DERATING
Maximum Leakage
Current/Clamping Voltage Curve
CURVE
MAXIMUM CLAMPING VOLTAGE
T2
100A
at -40ºC,
2. MAXIMUM LEAKAGE CURRENT/CLAMPING VOLTAGE CURVE FOR AUML SERIES AT 25 C
EXAMPLE:
25ºC, FIGURE
85ºC
and 125ºC
o
FOR AN 8/20 s CURRENT WAVEFORM
8 s = t1 = VIRTUAL FRONT TIME
MAXIMUM LEAKAGE
100
MAXIMUM CLAMPING VOLTAGE
100
20 s = t2 = VIRTUAL TIME TO
HALF VALUE
1210/1206
1812
1210/1206
10
VOLTAGE
VOLTAGE
2220
1812
2220
-40oC
10
25oC
85oC
125 oC
1
1
10µA
Figure 3
100µA
1mA
100mA
10mA
CURRENT
1A
10A
100A
FIGURE 2. MAXIMUM LEAKAGE CURRENT/CLAMPING VOLTAGE CURVE FOR AUML SERIES AT 25 oC
100
1µA
Figure 4
10µA
100µA
1mA
10mA
100mA
1A
10A
100A
1000A
CURRENT
FIGURE 3. TYPICAL V-I CHARACTERISTICS OF THE V18AUMLA2220 at -40 oC, 25oC, 85oC AND 125 oC
© 2020 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 01/27/20
Metal-Oxide Varistors (MOVs)
Surface Mount Multilayer Varistors (MLVs) > AUML Series
Temperature Effects
Speed of Response
In the leakage region of the AUML suppressor, the device
characteristics approaches a linear (ohmic) relationship
and shows a temperature dependent affect. In this region
the suppressor is in a high resistance mode (approaching
106Ω) and appears as a near open-circuit. Leakage currents
at maximum rated voltage are in the microamp range.
The clamping action of the AUML suppressor depends
on a conduction mechanism similar to that of other
semiconductor devices (i.e. P-N Junctions). The apparent
slow response time often associated with transient
voltage suppressors (Zeners, MOVs) is often due to
parasitic inductance in the package and leads of the
device and less dependent of the basic material (Silicon,
ZNO). Thus, the single most critical element affecting the
response time of any suppressor is its lead induc-tance.
The AUML suppressor is a surface mount device, with no
leads or external packaging, and thus, it has virtually zero
inductance. The actual response time of a AUML surge
suppressor is in the 1 to 5 ns range, more than sufficient
for the transients which are likely to be encountered in an
automotive environment.
Load Dump Energy Capability
A Load Dump transient occurs when the alternator load
in the automobile is abruptly reduced. The worst case
scenario of this transient occurs when the battery is
disconnected while operating at full rated load. There
are a number of different Load Dump specifications in
existence in the automotive industry, with the most
common one being that recommended by the Society of
Automotive Engineers, specification #SAE J1113. Because
of the diversity of these Load Dump specifications
Littelfuse defines the Load Dump energy capability of
the AUML suppressor range as that energy dissipated by
the device itself, independent of the test circuit setup.
The resultant Load Dump energy handling capability
serves as an excellent figure of merit for the AUML
suppressor. Standard Load Dump specifications require
a device capability of 10 pulses at rated energy, across
a temperature range of -40ºC to +125ºC. This capability
requirement is well within the ratings of all of the AUML
Series (Figure 6 on next page).
The very high energy absorption capability of the AUML
suppressor is achieved by means of a highly controlled
manufacturing process. This technology ensures that a
large volume of suppressor material, with an interdigitated
layer construction, is available for energy absorption in an
extremely small package. Unlike equivalent rated Silicon
TVS diodes, the entire AUML device volume is available to
dissipate the Load Dump energy.
Hence, the peak temperatures generated by the Load
Dump transient are significantly lower and evenly
dissipated throughout the complete device (Figure 5
below). This even energy dissipation ensures that there
are lower peak temperatures generated at the P-N grain
boundaries of the AUML suppressor.
Multilayer Internal Construction
Figure 5
AUML Load Dump Pulsing over a Temperature Range of
-55ºC to +125ºC
V(10mA)
35
2220 = 25J
1812 = 6J
1210 = 3J
30
25
VOLTAGE
When clamping transients at higher currents (at and above
the 10mA range), the AUML suppressor approaches
a 1-10 characteristic. In this region the characteristics
of the AUML are virtually temperature independent.
Figure 3 shows the typical effect of temperature on
the V-I characteristics of the AUML suppressor.
20
15
10
5
0
0
1
2
3
4
5
6
7
8
9
10
11
12
# OF LOAD DUMPS
Figure 6
FIGURE 5. AUML LOAD DUMP PULSING OVER A TEMPERATURE RANGE OF -55˚C TO 125˚C
There are a number of different size devices available in the
AUML Series, each one with a load dump energy rating,
which is size dependent.
V(10mA)
35
2220 = 25J
30
1210 = 3J
25
VOLTAGE
1812 = 6J
20
15
10
© 2020 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 01/27/20
5
0
0
50
100
150
200
250
300
# OF LOAD DUMPS
350
1,000
2,000
Metal-Oxide Varistors (MOVs)
Surface Mount Multilayer Varistors (MLVs) > AUML Series
Explanation of Terms
Maximum Continuous DC Working Voltage (VM*(DC)++)
This is the maximum continuous DC voltage which may
be applied, up to the maximum operating temperature
(125ºC), to the ML suppressor. This voltage is used as the
reference test point for leakage current and is always less
than the breakdown voltage of the device.
Load Dump Energy Rating WLD+
This is the actual energy the part is rated to dissipate
under Load Dump conditions (not to be confused with the
"source energy" of a Load Dump test specification).
Maximum Clamping Voltage VC+
This is the peak voltage appearing across the suppressor
when measured at conditions of specified pulse current
and specified waveform (8/20µs). It is important to note
that the peak current and peak voltage may not necessarily
be coincidental in time.
Leakage Current IL+
In the nonconducting mode, the device is at a very
high impedance (approaching 106Ω at its rated working
voltage) and appears as an almost open circuit in the
system. The leakage current drawn at this level is very
low ( AUML Series
Lead (Pb) Soldering Recommendations
The principal techniques used for the soldering of
components in surface mount technology are IR Re-flow
and Wave soldering. Typical profiles are shown on the right.
Reflow Solder Profile
The termination option available for each solder technique is:
230
Reflow
1. Nickel Barrier (preferred)
2. Silver/Platinum
Wave
1. Nickel Barrier (preferred)
230
The recommended solder for the AUML suppressor is
a 62/36/2 (Sn/Pb/Ag), 60/40 (Sn/Pb) or 63/37 (Sn/Pb).
Littelfuse also recommends an RMA solder flux.
Once the soldering process has been completed, it
is still necessary to ensure that any further thermal
shocks are avoided. One possible cause of thermal
shock is hot printed circuit boards being removed from
the solder process and subjected to cleaning solvents
at room temperature. The boards must be allowed to
cool gradually to less than 50ºC before cleaning.
FIGURE 8. REFLOW SOLDER PROFILE
FIGURE 8.
Wave Solder Profile
REFLOW SOLDER PROFILE
300
MAXIMUM WAVE 260 oC
300
250
o
TEMPERATURE
TEMPERATURE
( oC) ( C)
When using a reflow process, care should be taken to
ensure that the AUML chip is not subjected to a thermal
gradient steeper than 4 degrees per second; the ideal
gradient being 2 degrees per second. During the soldering
process, preheating to within 100 degrees of the solder's
peak temperature is essential to minimize thermal shock.
Figure 9
TEMPERATURE ( oC)
Wave soldering is the most strenuous of the processes.
To avoid the possibility of generating stresses due to
thermal shock, a preheat stage in the soldering process
is recommended, and the peak temperature of the solder
process should be rigidly controlled.
230
MAXIMUM WAVE 260 oC
250
200
FIGURE 8. REFLOW SOLDER PROFILE
200
150
SECOND PREHEAT
150
100
300
Figure 10
SECOND PREHEAT
FIRST PREHEAT
MAXIMUM WAVE 260 oC
100
50
250
FIRST PREHEAT
50
0
2000.0
0.5
1.0
1.5
4.0
4.5
0
150 0.0
0.5
1.0
1.5
4.0
4.5
4.0
4.5
100
2.0
2.5
3.0
3.5
TIME (MINUTES)
2.0
2.5
3.0
3.5
TIMESOLDER
(MINUTES)
SECONDPROFILE
PREHEAT
FIGURE 9. WAVE
FIGURE 9. WAVE SOLDER PROFILE
FIRST PREHEAT
50
Lead–free (Pb-free) Soldering Recommendations
Littelfuse offers the Nickel Barrier Termination finish for the
optimum Lead–free solder performance.
0
0.0
Note: the Lead–free paste, flux and profile were used for
evaluation purposes by Littelfuse, based upon industry
standards and practices. There are multiple choices of all
three available, it is advised that the customer explores the
optimum combination for their process as processes vary
considerably from site to site.
3.5
20 - 40 SECONDS
WITHIN
5˚C
RAMP
RATE
217˚C
RAMP RATE
217˚C
Lead–free Re-flow Solder Profile
The preferred solder is 96.5/3.0/0.5 (SnAgCu) with an RMA
flux, but there is a wide selection of pastes and fluxes
available with which the Nickel Barrier parts should be
compatible.
The reflow profile must be constrained by the maximums
in the Lead–free Reflow Profile. For Lead–free Wave
soldering, the Wave Solder Profile still applies.
MAXIMUM TEMPERATURE 260˚C
0.520 - 40
1.0 SECONDS
1.5
2.0
2.5
WITHIN
5˚C 3.0
TIME (MINUTES)
MAXIMUM TEMPERATURE
260˚C
PREHEAT ZONE
MAXIMUM TEMPERATURE 260˚C
20PREHEAT
- 40 SECONDS
ZONEWITHIN 5˚C
RAMP RATE
217˚C
7.0
5.0
7.0
6.0
FIGURE 10. LEAD-FREE RE-FLOW SOLDER PROFILE
FIGURE PREHEAT
10. LEAD-FREE
ZONE RE-FLOW SOLDER PROFILE
5.0
6.0
7.0
Figure 11
FIGURE 10. LEAD-FREE RE-FLOW SOLDER PROFILE
© 2020 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 01/27/20
Metal-Oxide Varistors (MOVs)
Surface Mount Multilayer Varistors (MLVs) > AUML Series
Product Dimensions (mm)
PAD LAYOUT DIMENSIONS
CHIP LAYOUT DIMENSIONS
E
Note: Avoid metal runs in this area,
parts are not recommended for use
in applications using silver (Ag)
expoxy paste.
L
D
W
Note: Avoid metal runs in this area, parts are not recommended
for use in applications using Silver (Ag) epoxy paste.
1206 Size
SYMBOL
1210 Size
1812 Size
2220 Size
IN
MM
IN
MM
IN
MM
IN
MM
0.203
5.150
0.219
5.510
0.272
6.910
0.315
8.000
B
0.103
2.620
0.147
3.730
0.172
4.360
0.240
6.190
C
0.065
1.650
0.073
1.850
0.073
1.850
0.073
1.850
A
D (max.)
0.071
1.80
0.070
1.80
0.07
1.80
0.118
3.00
E
0.020 -/+ 0.010
0.50 -/+0.25
0.020 -/+ 0.010
0.50 -/+ 0.25
0.020 -/+ 0.010
0.50 -/+ 0.25
0.030 -/+ 0.010
0.75 -/+ 0.25
L
0.125 -/+ 0.012
3.20 -/+ 0.03
0.125 -/+ 0.012
3.20 -/+ 0.30
0.180 -/+ 0.014
4.50 -/+ 0.35
0.225 -/+ 0.016
5.70 -/+ 0.40
W
0.060 -/+ 0.011
1.60 -/+ 0.28
0.100 -/+ 0.012
2.54 -/+ 0.30
0.125 -/+ 0.012
3.20 -/+ 0.30
0.197 -/+ 0.016
5.00 -/+ 0.40
Part Numbering System
V 18 AUML A 2220 X X
DEVICE FAMILY
TVSS Device
MAXIMUM DC
WORKING VOLTAGE
AUTOMOTIVE
MULTILAYER DESIGNATOR
LOAD DUMP ENERGY RATING
INDICATOR
PACKING OPTIONS
A: Bulk Pack, 2500 pieces
H: 7in (178mm) Diameter Reel*
T: 13in (330mm) Diameter Reel*
* See quanttities in Packaging table below
END TERMINATION OPTION
N or No Letter: Nickel Barrier
DEVICE SIZE
i.e., 220 mil x 200 mil
Packaging*
Device Size
1206
Quantity
13” Inch Reel
('T' Option)
10,000
7” Inch Reel
('H' Option)
2,500
Bulk Pack
('A' Option)
2,500
1210
8,000
2,000
2,000
1812
4,000
1,000
1,000
2220
4,000
1,000
1,000
*(Packaging) It is recommended that parts be kept in the sealed bag provided and that parts be used as soon as possible when removed from bags.
© 2020 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 01/27/20
Metal-Oxide Varistors (MOVs)
Surface Mount Multilayer Varistors (MLVs) > AUML Series
Tape and Reel Specifications
Symbol
Description
Dimensions in Millimeters
A0
Width of Cavity
Dependent on Chip Size to Minimize Rotation.
B0
Length of Cavity
Dependent on Chip Size to Minimize Rotation.
K0
Depth of Cavity
Dependent on Chip Size to Minimize Rotation.
W
Width of Tape
8 -/+ 0.2
12 -/+ 0.2
F
Distance Between Drive Hole Centers and Cavity Centers
3.5 -/+ 0.5
5.4 -/+ 0.5
E
Distance Between Drive Hole Centers and Tape Edge
1.75 -/+ 0.1
1.75 -/+ 0.1
P1
Distance Between Cavity Center
4 -/+ 0.1
8-/+ 0.1
P2
Axial Distance Between Drive Hole Centers and Cavity Centers
2 -/+ 0.1
2 -/+ 0.1
P0
Axial Distance Between Drive Hole Centers
8 -/+ 0.1
8 -/+ 0.1
D0
Drive Hole Diameter
1.55 -/+ 0.05
1.55 -/+ 0.05
D1
Diameter of Cavity Piercing
1.05 -/+ 0.05
1.55 -/+ 0.05
T1
Embossed Tape Thickness
0.3 Max
0.4 Max
T2
Top Tape Thickness
0.1 Max
0.1 Max
NOTE: Dimensions in millimeters.
• Conforms to EIA-481-1, Revision A
• Can be supplied to IEC publication 286-3
Tape
Chip Size
8mm Wide Tape
1206
1210
12mm Wide Tape
1812
2220
Standard Packaging
Special Packaging
Tape and reel is the standard packaging method of the
AUML Series. The standard 300 millimeter (13–inch) reel
utilized contains 4000 pieces for the 2200 and 1812 chips,
8000 pieces for the 1210 chip and 10,000 pieces for the
1206 size.
Option1:
To order: add 'T' to the standard part number,
e.g.V18AUMLA222OT.
178 millimeter (7–inch) reels containing 1000
(2220, 1812), 2000 (1210), 2500 (1206), pieces
are available. To order add 'H' to the standard
part number, e.g. V18AUMLA2220H.
Option 2 For small sample quantities (less than 100
pieces) the units are shipped bulk pack. To
order add 'A' to the standard part number,
e.g. V18AUMLA2220A.
Disclaimer Notice - Information furnished is believed to be accurate and reliable. However, users should independently evaluate the suitability of and
test each product selected for their own applications. Littelfuse products are not designed for, and may not be used in, all applications.
Read complete Disclaimer Notice at www.littelfuse.com/disclaimer-electronics.
© 2020 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 01/27/20
