Littelfuse AUML User Manual
Varistor Products
Surface Mount Multilayer Varistors (MLVs) > AUML Series
AUML Varistor Series
Size Table
Metric EIA
3216 1206
3225 1210
4532 1812
5650 2220
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 -55ºC to 125ºC.
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.
AUML Series
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, MILSTD-883C, Method
3015.7, and other
industry specifications
(See Also the MLE
or MLN Series)
• Provides on-board
transient voltage
protection for ICs
and transistors
• Used to help achieve
electromagnetic
compliance of
end products
• Replace larger surface
mount TVS Zeners in
many applications
Features
• AEC - Q200 compliant
• RoHS Compliant
• Load Dump energy
rated per SAE
Specification J1113
• Leadless, surface
mount chip form
• “Zero” Lead
Inductance
• Variety of energy
ratings available
• No temperature
derating up to
• High peak surge
current capability
• Low Profile, compact
industry standard
chip size; (1206, 1210,
1812 and 2220 Sizes)
• Inherent bidirectional
clamping
• No Plastic or epoxy
packaging assures
better than 94V-0
flammability rating
125ºC ambient
Absolute Maximum Ratings
• For ratings of individual members of a series, see Device Ratings and Specifications chart.
Continuous AUML Series Units
Steady State Applied Voltage:
DC Voltage Range (V
Transient:
Load Dump Energy, (WLD) 1.5 to 25 J
Jump Start Capability (5 minutes), (V
Operating Ambient Temperature Range (T
Storage Temperature Range (T
Temperature Coefficient (DV) of Clamping Voltage (V
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any
other conditions above those indicated in the operational sections of this specification is not implied.
) -55 to +150
STG
) 18 V
M(DC)
) 24.5 V
) -55 to +125
A
JUMP
) at Specified Test Current
C
<0.01 %/OC
O
C
O
C
© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/AUML.html for current information.
55
Revised: May 8, 2013
AUML Varistor Series
Varistor Products
Surface Mount Multilayer Varistors (MLVs) > AUML Series
Device Ratings and Specifications
ºC
Maximum Ratings (125
Part Number
Maximum
Continuous
DC Voltage
V
M(DC)
Jump Start
Voltage
(5 Min)
V
JUMP
(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
For automotive 24V and 42V applications please contact your Littelfuse representative or visit www.littelfuse.com for the latest product update.
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 energy rating (into the suppressor) of a voltage transient with a resultant time constant of 115ms to 230ms.
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.
) Specifications (25ºC)
Load Dump
Energy
(10 Pulses)
W
LD
Nominal Varistor Voltage
at 10mA
DC Test Current
V
Min V
N(DC)
Max I
N(DC)
Maximum
Standby Leakage
(at 13V DC)
Maximum Clamping
Voltage (V
Test Current (8/20μs)
L
V
C
C
) at
I
P
Current, Energy and Power Derating Curve
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.
100
90
80
70
60
50
40
30
20
PERCENT OF RATED VALUE
10
0
-55 50 60 70 80 90 10 0 110 120 130 140 150
Figure 1
AMBIENT TEMPERATURE (oC)
Maximum Leakage Current/Clamping Voltage Curve for
AUML Series at 25ºC
Peak Pulse Current Test Waveform for Clamping Voltage
100
50
0
PERCENT OF PEAK VALUE
O
1
Figure 2
T
T
1
T
2
TIME
01 = Virtual Origin of Wave
T = Time from 10% to 90% of Peak
T1 = Rise Time = 1.25 x T
T2 = Decay Time
Example - For an 8/20 μs Current Waveform:
8μs = T
= Rise Time
1
20μs = T
= Decay Time
2
Typical V-I Characteristics of the V18AUMLA2220 at -40ºC,
25ºC, 85ºC and 125ºC
100
10
VOLTA GE
1
Figure 3 Figure 4
AUML Varistor Series
MAXIMUM LEAKAGE MAXIMUM CLAMPING VOLTAGE
1210/1206
1812
2220
10mA
CURRENT
100mA
1mA
100μA10μA
1A 10A
1210/1206
1812
2220
100A
Revised: May 8, 2013
100
10
VOLTA GE
1
56
-40oC
25oC
85oC
125oC
1μA 10μA 100μA
Please refer to www.littelfuse.com/series/AUML.html for current information.
10mA 100mA 1A 10A 100A 1000A
1mA
CURRENT
Specifications are subject to change without notice.
© 2013 Littelfuse, Inc.
Varistor Products
Surface Mount Multilayer Varistors (MLVs) > AUML Series
Temperature Effects
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.
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).
Further testing on the AUML Series has concentrated
on extending the number of Load Dump pulses, at rated
energy, which are applied to the devices. The reliability
information thus generated gives an indication of the
inherent capability of these devices. As an example of
device durability the 1210 size has been subjected to over
2000 pulses at its rated energy of 3 joules (J); the 1812 size
has been pulsed over 1000 times at 6J and 2220 size has
been pulsed at its rated energy of 25J over 300 times. In
all cases there has been little or no change in the device
characteristics (Figure 7 on next page).
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.
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.
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.
Experience has shown that while the effects of a load dump
tranient is of real concern, its frequency of occurrence is
much less than thoe of low energy inductive spikes. Such
low energy inductive spikes may be generated as a result
of motors switching on and off, from ESD occurrances, fuse
blowing, etc. It is essential that the suppression technology
selected also has the capability to suppress such transients.
Testing on the V18AUMLA2220 has shown that after being
subjected to a repetitive energy pulse of 2J, over 6000
times, no characteristic changes have occurred (Figure 8 on
next page).
AUML Series
Speed of Response
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,
Z
O). Thus, the single most critical element affecting the
N
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.
© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/AUML.html for current information.
57
Revised: May 8, 2013
Multilayer Internal Construction
Figure 5
AUML Varistor Series
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