WS1403 Ver la hoja de datos (PDF) - Avago Technologies
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WS1403 Datasheet PDF : 15 Pages
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Storage Condition
Packages described in this document must be stored
in sealed moisture barrier, antistatic bags. Shelf life in a
sealed moisture barrier bag is 12 months at <40°C and
90% relative humidity (RH) J-STD-033 p.7.
Out-of-Bag Time Duration
After unpacking, the device must be soldered to the PCB
within 168 hours as listed in the J-STD-020B p.11 with
factory conditions <30°C and 60% RH.
Baking
It is not necessary to re-bake the part if both conditions
(storage conditions and out-of bag conditions) have
been satisfied. Baking must be done if at least one of
the conditions above have not been satisfied. The baking
conditions are 125°C for 12 hours J-STD-033 p.8.
CAUTION
Tape and reel materials typically cannot be baked at the
temperature described above. If out-of-bag exposure
time is exceeded, parts must be baked for a longer time
at low temperatures, or the parts must be de-reeled, de-
taped, re-baked and then put back on tape and reel. (See
moisture sensitive warning label on each shipping bag
for information of baking).
Board Rework
Component Removal, Rework and Remount
If a component is to be removed from the board, it is
recommended that localized heating be used and the
maximum body temperatures of any surface mount
component on the board not exceed 200°C. This
method will minimize moisture related component
damage. If any component temperature exceeds 200°C,
the board must be baked dry per 4-2 prior to rework
and/or component removal. Component temperatures
shall be measured at the top center of the package body.
Any SMD packages that have not exceeded their floor
life can be exposed to a maximum body temperature as
high as their specified maximum reflow temperature.
Removal for Failure Analysis
Not following the above requirements may cause
moisture/reflow damage that could hinder or
completely prevent the determination of the original
failure mechanism.
Baking of Populated Boards
Some SMD packages and board materials are not able
to withstand long duration bakes at 125°C. Examples of
this are some FR-4 materials, which cannot withstand a
24 hr bake at 125°C. Batteries and electrolytic capacitors
are also temperature sensitive. With component and
board temperature restrictions in mind, choose a
bake temperature from Table 4-1 in J-STD 033; then
determine the appropriate bake duration based on the
component to be removed. For additional considerations
see IPC-7711 and IPC-7721.
Derating Due to Factory Environmental Conditions
Factory floor life exposures for SMD packages removed
from the dry bags will be a function of the ambient
environmental conditions. A safe, yet conservative,
handling approach is to expose the SMD packages only
up to the maximum time limits for each moisture
sensitivity level as shown in Table 7. This approach,
however, does not work if the factory humidity or
temperature is greater than the testing conditions of
30°C/60% RH. A solution for addressing this problem
is to derate the exposure times based on the knowledge
of moisture diffusion in the component package
materials ref. JESD22-A120). Recommended equivalent
total floor life exposures can be estimated for a range
of humidities and temperatures based on the nominal
plastic thickness for each device.
Table 8 lists equivalent derated floor lives for humidities
ranging from 20-90% RH for three temperature, 20°C,
25°C, and 30°C.
This table is applicable to SMDs molded with novolac,
biphenyl or multifunctional epoxy mold compounds.
The following assumptions were used in calculating
Table 8:
1. Activation Energy for diffusion = 0.35eV (smallest
known value).
2. For ≤60% RH, use Diffusivity = 0.121exp ( -0.35eV/kT)
mm2/s
(this used smallest known Diffusivity @ 30°C).
3. For >60% RH, use Diffusivity = 1.320exp ( -0.35eV/kT)
mm2/s
(this used largest known Diffusivity @ 30°C).
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