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Varistor Products
©2009 Littelfuse, Inc.
Revision: November 5, 2009
AUML Varistor Series
Surface Mount Multilayer Varistors (MLVs) > AUML Series
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/AUML.html for current information.
Product Dimensions (mm)
Note: Avoid metal runs in this area, parts are not recommended
for use in applications using Silver (Ag) epoxy paste.
D
E
W
L
SYMBOL
1206 Size
1210 Size
1812 Size
2220 Size
IN
MM
IN
MM
IN
MM
IN
MM
A
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
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
PAD LAYOUT DIMENSIONS
CHIP LAYOUT DIMENSIONS
Explanation of Terms
Maximum Continuous DC Working Voltage (*V
M*(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 *W
LD+
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 *V
C+
This is the peak voltage appearing across the suppressor
when measured at conditions of specified pulse current
and specified waveform (8/20s). It is important to note
that the peak current and peak voltage may not necessarily
be coincidental in time.
Leakage Current *I
L+
In the nonconducting mode, the device is at a very
high impedance (approaching 10
6
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 (<25A at ambient temperature) and, unlike the
Zener diode, the multilayer TVS has the added advantage
that, when operated up to its maximum temperature,
its leakage current will not increase above 500A.
Nominal Voltage *V
N*DC++
This is the voltage at which the AUML enters its
conduction state and begins to suppress transients.
In the automotive environment this voltage is
defined at the 10mA point and has a minimum
(V
N(DC) MIN
) and maximum (V
N(DC) MAX
) voltage specified.
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 5).