V0402MHS03N_10 Datasheet, PDF (3/5 Pages) Littelfuse – Surface Mount Multilayer Varistors (MLVs)

Varistor Products
Surface Mount Multilayer Varistors (MLVs) > MHS Series
Device Characteristics
At low current levels, the V-I curve of the multilayer
transient voltage suppressor approaches a linear (ohmic)
relationship and shows a temperature dependent effect.
At or below the maximum working voltage, the suppressor
is in a high resistance model (approaching 10⁶Ω at its
maximum rated working voltage). Leakage currents at
maximum rated voltage are below 100μA, typically 25μA;
for 0402 size below 20μA, typically 5μA.
Typical Temperature Dependance of the Characteristic
Curve in the Leakage Region
100%
Speed of Response
The Multilayer Suppressor is a leadless device. Its
response time is not limited by the parasitic lead
inductances found in other surface mount packages.
The response time of the Z_NO dielectric material is less
than 1ns and the MLE can clamp very fast dV/dT events
such as ESD. Additionally, in “real world” applications,
the associated circuit wiring is often the greatest
factor effecting speed of response. Therefore, transient
suppressor placement within a circuit can be considered
important in certain instances.
Multilayer Internal Construction
FIRED CERAMIC
DIELECTRIC
10%
1E^-9
Figure 5
25^o 50^o 75^o 100^o 125^oC
1E^-8
1E^-7
1E^-6
1E^-5
1E^-4
SUPPRESSOR CURRENT (A_DC)
1E^-3
1E^-2
METAL END
TERMINATION
Figure 6
DEPLETION
REGION
DEPLETION
REGION
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.
The recommended solder for the MHS 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.
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.
When using a reflow process, care should be taken to
ensure that the MHS 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.
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.
Reflow Solder Profile
Figure 7
Wave Solder Profile
METAL
ELECTRODES
GRAINS
230
©2010 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/MHS.html for current information.
Figure 8
Revision: June 28, 2010
MHS Varistor Series