NQB-420DWA-AN Datasheet, PDF (32/36 Pages) CUI INC – FULLY REGULATED ADVANCED BUS CONVERTERS

CUI Inc │ SERIES: NQB-D │ DESCRIPTION: FULLY REGULATED ADVANCED BUS CONVERTERS
date 02/20/2013 │ page 32 of 36
Soldering Information - Surface Mounting
The surface mount product is intended for forced
convection or vapor phase reflow soldering in SnPb and
Pb-free processes.
The reflow profile should be optimised to avoid excessive
heating of the product. It is recommended to have
a sufficiently extended preheat time to ensure an
even temperature across the host PWB and it is also
recommended to minimize the time in reflow.
A no-clean flux is recommended to avoid entrapment of
cleaning fluids in cavities inside the product or between
the product and the host board, since cleaning residues
may affect long time reliability and isolation voltage.
General reflow process specifications SnPb eutectic Pb-free
Average ramp-up (T PRODUCT)
Typical solder melting (liquidus)
temperature
Minimum reflow time above T L
Minimum pin temperature
Peak product temperature
Average ramp-down (T PRODUCT)
Maximum time 25°C to peak
TL
T PIN
T PRODUCT
3°C/s max
183°C
60 s
210°C
225°C
6°C/s max
6 minutes
3°C/s max
221°C
60 s
235°C
260°C
6°C/s max
8 minutes
Lead-free (Pb-free) solder processes
For Pb-free solder processes, a pin temperature (T_PIN)
in excess of the solder melting temperature (T_L, 217 to
221°C for SnAgCu solder alloys) for more than 60 seconds
and a peak temperature of 245°C on all solder joints is
recommended to ensure a reliable solder joint.
Maximum Product Temperature Requirements
Top of the product PWB near pin 2 is chosen as reference
location for the maximum (peak) allowed product
temperature (T_PRODUCT) since this will likely be the warmest
part of the product during the reflow process.
SnPb solder processes
For SnPb solder processes, the product is qualified for MSL
1 according to IPC/JEDEC standard J STD 020C.
During reflow T_PRODUCT must not exceed 225 °C at any time.
Pb-free solder processes
For Pb-free solder processes, the product is qualified for
MSL 3 according to IPC/JEDEC standard J-STD-020C.
During reflow T_PRODUCT must not exceed 260 °C at any time.
Dry Pack Information
Tem per at ur e
T_PRODUCT maximum
T_PIN minimum
T_L
Time in preheat
/ soak zone
Time in
reflow
Time 25°C to peak
Pin
profile
Product
profile
Tim e
Products intended for Pb-free reflow soldering processes
are delivered in standard moisture barrier bags according
to IPC/JEDEC standard J STD 033 (Handling, packing,
shipping and use of moisture/reflow sensitivity surface
mount devices).
Using products in high temperature Pb-free soldering
processes requires dry pack storage and handling. In
case the products have been stored in an uncontrolled
environment and no longer can be considered dry, the
modules must be baked according to J STD 033.
Minimum Pin Temperature Recommendations
Pin number 5 chosen as reference location for the
minimum pin temperature recommendation since this will
likely be the coolest solder joint during the reflow process.
Thermocoupler Attachment
Top of PWB near pin 2 for measurement of maximum
product temperature, T_PRODUCT
SnPb solder processes
For SnPb solder processes, a pin temperature (TPIN) in
excess of the solder melting temperature, (TL, 183°C
for Sn63Pb37) for more than 60 seconds and a peak
temperature of 220°C is recommended to ensure a reliable
solder joint.
For dry packed products only: depending on the type of
solder paste and flux system used on the host board, up to
a recommended maximum temperature of 245°C could be
used, if the products are kept in a controlled environment
(dry pack handling and storage) prior to assembly.
Pin 5 for measurement of minimum pin (solder joint )
temperature, T_PIN
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