Datasheet

cui.com
date 11/07/2014 │ page 32 of 36CUI Inc │ SERIES: NQB-D │ DESCRIPTION: FULLY REGULATED ADVANCED BUS CONVERTERS
Soldering Information - Surface Mounting
Minimum Pin Temperature Recommendations
The surface mount product is intended for forced
convection or vapor phase reow soldering in SnPb and
Pb-free processes.
The reow prole should be optimised to avoid excessive
heating of the product. It is recommended to have
a sufciently extended preheat time to ensure an
even temperature across the host PWB and it is also
recommended to minimize the time in reow.
A no-clean ux is recommended to avoid entrapment of
cleaning uids in cavities inside the product or between
the product and the host board, since cleaning residues
may affect long time reliability and isolation voltage.
Average ramp-up (T
PRODUCT
)3°C/s max3°C/s max
Typical solder melting (liquidus)
temperature
T183°C
L
221°C
Minimum reflow time above T
L
60 s60 s
Minimum pin temperatureT 210°C
PIN
235°C
Peak product temperatureT 225°C
PRODUCT
260°C
Average ramp-down (T
PRODUCT
)6°C/s max6°C/s max
Maximum time 25°C to peak 6 minutes 8 minutes
T
PRODUCT
maximum
T
PIN
minimum
Time
niP
profile
Product
profile
T
L
Time in
reflow
Time in preheat
/ soak zone
Time 25°C to peak
Temperature
General reflow process specifications
SnPb eutectic
Pb-free
Pin number 5 chosen as reference location for the
minimum pin temperature recommendation since this will
likely be the coolest solder joint during the reow process.
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 ux 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.
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 reow process.
SnPb solder processes
For SnPb solder processes, the product is qualied for MSL
1 according to IPC/JEDEC standard J STD 020C.
During reow T
PRODUCT
must not exceed 225 °C at any time.
Pb-free solder processes
For Pb-free solder processes, the product is qualied for
MSL 3 according to IPC/JEDEC standard J-STD-020C.
During reow T
PRODUCT
must not exceed 260 °C at any time.
Dry Pack Information
Products intended for Pb-free reow soldering processes
are delivered in standard moisture barrier bags according
to IPC/JEDEC standard J STD 033 (Handling, packing,
shipping and use of moisture/reow 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.
Thermocoupler Attachment
Top of PWB near pin 2 for measurement of maximum
product temperature, T
PRODUCT
Pin 5 for measurement of minimum pin (solder joint )
temperature, T
PIN
For more information, please visit the product page.