參數(shù)資料
型號: P89C739ABB
廠商: NXP SEMICONDUCTORS
元件分類: 微控制器/微處理器
英文描述: 8-bit Flash microcontrollers
中文描述: 8-BIT, FLASH, 40 MHz, MICROCONTROLLER, PQFP64
封裝: 14 X 20 MM, 2.70 MM HEIGHT, PLASTIC, SOT-319-1, QFP-64
文件頁數(shù): 62/64頁
文件大?。?/td> 360K
代理商: P89C739ABB
1998 Apr 07
62
Philips Semiconductors
Product specification
8-bit Flash microcontrollers
P89C738; P89C739
23 SOLDERING
23.1
Introduction
There is no soldering method that is ideal for all IC
packages. Wave soldering is often preferred when
through-hole and surface mounted components are mixed
on one printed-circuit board. However, wave soldering is
not always suitable for surface mounted ICs, or for
printed-circuits with high population densities. In these
situations reflow soldering is often used.
This text gives a very brief insight to a complex technology.
A more in-depth account of soldering ICs can be found in
our “Data Handbook IC26; Integrated Circuit Packages”
(order code 9398 652 90011).
23.2
DIP
23.2.1
S
OLDERING BY DIPPING OR BY WAVE
The maximum permissible temperature of the solder is
260
°
C; solder at this temperature must not be in contact
with the joint for more than 5 seconds. The total contact
time of successive solder waves must not exceed
5 seconds.
The device may be mounted up to the seating plane, but
the temperature of the plastic body must not exceed the
specified maximum storage temperature (T
stg max
). If the
printed-circuit board has been pre-heated, forced cooling
may be necessary immediately after soldering to keep the
temperature within the permissible limit.
23.2.2
R
EPAIRING SOLDERED JOINTS
Apply a low voltage soldering iron (less than 24 V) to the
lead(s) of the package, below the seating plane or not
more than 2 mm above it. If the temperature of the
soldering iron bit is less than 300
°
C it may remain in
contact for up to 10 seconds. If the bit temperature is
between 300 and 400
°
C, contact may be up to 5 seconds.
23.3
PLCC and QFP
23.3.1
R
EFLOW SOLDERING
Reflow soldering techniques are suitable for all PLCC and
QFP packages.
The choice of heating method may be influenced by larger
plastic PLCC and QFP packages (44 leads, or more).
If infrared or vapour phase heating is used and the large
packages are not absolutely dry (less than 0.1% moisture
content by weight), vaporization of the small amount of
moisture in them can cause cracking of the plastic body.
For details, refer to the Drypack information in the
“Data Handbook IC26; Integrated Circuit Packages;
Section: Packing Methods”
Reflow soldering requires solder paste (a suspension of
fine solder particles, flux and binding agent) to be applied
to the printed-circuit board by screen printing, stencilling or
pressure-syringe dispensing before package placement.
Several methods exist for reflowing; for example,
infrared/convection heating in a conveyor type oven.
Throughput times (preheating, soldering and cooling) vary
between 50 and 300 seconds depending on heating
method. Typical reflow peak temperatures range from
215 to 250
°
C.
23.3.2
W
AVE SOLDERING
23.3.2.1
PLCC
Wave soldering techniques can be used for all PLCC
packages if the following conditions are observed:
A double-wave (a turbulent wave with high upward
pressure followed by a smooth laminar wave) soldering
technique should be used.
The longitudinal axis of the package footprint must be
parallel to the solder flow.
The package footprint must incorporate solder thieves at
the downstream corners.
23.3.2.2
QFP
Wave soldering is
not
recommended for QFP packages.
This is because of the likelihood of solder bridging due to
closely-spaced leads and the possibility of incomplete
solder penetration in multi-lead devices.
If wave soldering cannot be avoided, for QFP
packages with a pitch (e) larger than 0.5 mm, the
following conditions must be observed:
A double-wave (a turbulent wave with high upward
pressure followed by a smooth laminar wave)
soldering technique should be used.
The footprint must be at an angle of 45
°
to the board
direction and must incorporate solder thieves
downstream and at the side corners.
CAUTION
Wave soldering is NOT applicable for all QFP
packages with a pitch (e) equal or less than 0.5 mm.
相關PDF資料
PDF描述
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P89C739 8-bit Flash microcontrollers
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