- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄372109 > SAA4978H (NXP SEMICONDUCTORS) Picture Improved Combined Network PICNIC PDF資料下載
參數(shù)資料
| 型號： | SAA4978H |
| 廠商： | NXP SEMICONDUCTORS |
| 元件分類： | 消費家電 |
| 英文描述： | Picture Improved Combined Network PICNIC |
| 中文描述： | SPECIALTY CONSUMER CIRCUIT, PQFP160 |
| 封裝： | 28 X 28 MM, 3.40 MM HEIGHT, PLASTIC, MS-022, SOT-322-2, QFP-160 |
| 文件頁數(shù)： | 53/56頁 |
| 文件大?。?/td> | 296K |
| 代理商： | SAA4978H |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁第46頁第47頁第48頁第49頁第50頁第51頁第52頁當(dāng)前第53頁第54頁第55頁第56頁
1999 May 03
53
Philips Semiconductors
Product specification
Picture Improved Combined Network
(PICNIC)
SAA4978H
14 SOLDERING
14.1
Introduction to soldering surface mount
packages
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”
(document order number 9398 652 90011).
There is no soldering method that is ideal for all surface
mount IC packages. Wave soldering is not always suitable
for surface mount ICs, or for printed-circuit boards with
high population densities. In these situations reflow
soldering is often used.
14.2
Reflow soldering
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 100 and 200 seconds depending on heating
method.
Typical reflow peak temperatures range from
215 to 250
°
C. The top-surface temperature of the
packages should preferable be kept below 230
°
C.
14.3
Wave soldering
Conventional single wave soldering is not recommended
for surface mount devices (SMDs) or printed-circuit boards
with a high component density, as solder bridging and
non-wetting can present major problems.
To overcome these problems the double-wave soldering
method was specifically developed.
If wave soldering is used the following conditions must be
observed for optimal results:
Use a double-wave soldering method comprising a
turbulent wave with high upward pressure followed by a
smooth laminar wave.
For packages with leads on two sides and a pitch (e):
– larger than or equal to 1.27 mm, the footprint
longitudinal axis is
preferred
to be parallel to the
transport direction of the printed-circuit board;
– smaller than 1.27 mm, the footprint longitudinal axis
must
be parallel to the transport direction of the
printed-circuit board.
The footprint must incorporate solder thieves at the
downstream end.
For packages with leads on four sides, the footprint must
be placed at a 45
°
angle to the transport direction of the
printed-circuit board. The footprint must incorporate
solder thieves downstream and at the side corners.
During placement and before soldering, the package must
be fixed with a droplet of adhesive. The adhesive can be
applied by screen printing, pin transfer or syringe
dispensing. The package can be soldered after the
adhesive is cured.
Typical dwell time is 4 seconds at 250
°
C.
A mildly-activated flux will eliminate the need for removal
of corrosive residues in most applications.
14.4
Manual soldering
Fix the component by first soldering two
diagonally-opposite end leads. Use a low voltage (24 V or
less) soldering iron applied to the flat part of the lead.
Contact time must be limited to 10 seconds at up to
300
°
C.
When using a dedicated tool, all other leads can be
soldered in one operation within 2 to 5 seconds between
270 and 320
°
C.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SAA4979H | Sample rate converter with embedded high quality dynamic noise reduction and expansion port |
| SAA4981 | Monolithic integrated 16 : 9 compressor |
| SAA4981T | Monolithic integrated 16 : 9 compressor |
| SAA4993H | Field and line rate converter with noise reduction |
| SAA4994H | Field and line rate converter with noise reduction |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SAA4979H | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Sample rate converter with embedded high quality dynamic noise reduction and expansion port |
| SAA4981 | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Monolithic integrated 16 : 9 compressor |
| SAA4981T | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Monolithic integrated 16 : 9 compressor |
| SAA4990 | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Progressive scan-Zoom and Noise reduction IC PROZONIC |
| SAA4990H | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Progressive scan-Zoom and Noise reduction IC PROZONIC |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。