
AN1005
Application Notes
http://www.teccor.com
+1 972-580-7777 
AN1005 - 4
2002 Teccor Electronics
Thyristor Product Catalog
Gluing Recommendations
Prior to wave soldering, surface mount devices (SMDs) must be 
fixed to the PCB or substrate by means of an appropriate adhe-
sive. The adhesive (in most cases a multicomponent adhesive) 
has to fulfill the following demands:
Uniform viscosity to ensure easy coating
No chemical reactions upon hardening in order not to deterio-
rate component and PC board
Straightforward exchange of components in case of repair
Low-temperature Solder for Reducing
PC Board Damage
In testing and troubleshooting surface-mounted components, 
changing parts can be time consuming. Moreover, desoldering 
and soldering cycles can loosen and damage circuit-board pads. 
Use low-temperature solder to minimize damage to the PC board 
and to quickly remove a component. One low-temperature alloy 
is indium-tin, in a 50/50 mixture. It melts between 118 °C and 
125 °C, and tin-lead melts at 183 °C. If a component needs 
replacement, holding the board upside down and heating the 
area with a heat gun will cause the component to fall off. Per-
forming the operation quickly minimizes damage to the board and 
component.
Proper surface preparation is necessary for the In-Sn alloy to wet 
the surface of the copper. The copper must be clean, and you 
must add flux to allow the alloy to flow freely.You can use rosin 
dissolved in alcohol. Perform the following steps:
(1) Cut a small piece of solder and flow it onto one of the pads.
(2) Place the surface-mount component on the pad and melt the 
soldered pad to its pin while aligning the part. (This operation 
places all the pins flat onto their pads.)
(3) Cut small pieces of the alloy solder and flow each piece onto 
each of the other legs of the component.
Indium-tin solder is available from ACI Alloys, San Jose, CA and 
Indium Corporation of America, Utica, NY.
Multi-use Footprint
Package soldering footprints can be designed to accommodate 
more than one package. Figure AN1005.8 shows a footprint 
design for using both the Compak and an SOT-223. Using the 
dual pad outline makes it possible to use more than one supplier 
source.
Cleaning Recommendations
Using solvents for PC board or substrate cleaning is permitted 
from approximately 70 °C to 80 °C.
The soldered parts should be cleaned with azeotrope solvent fol-
lowed by a solvent such as methol, ethyl, or isopropyl alcohol.
Ultrasonic cleaning of surface mount components on PCBs or 
substrates is possible.
The following guidelines are recommended when using ultra-
sonic cleaning:
Cleaning agent: Isopropanol
Bath temperature: approximately 30 °C
Duration of cleaning: MAX 30 seconds
Ultrasonic frequency: 40 kHz
Ultrasonic changing pressure: approximately 0.5 bar
Cleaning of the parts is best accomplished using an ultrasonic 
cleaner which has approximately 20 W of output per one liter of 
solvent. Replace the solvent on a regular basis.
Figure AN1005.8
Dual Footprint for 
Compak
 Package
MT2 / Anode
Compak
Footprint
Footprint
for either
Compak
or SOT-223
Dual Pad Outline
Pad Outline
0.150
(3.8)
0.328
(8.33)
0.079
(2.0)
0.030
(.76)
0.040
(1.0)
0.019
(.48)
0.079
(2.0)
0.091
(2.31)
0.079
(2.0)
.055
(1.4)
0.059
(1.5)
TYP
TYP
0.079
(2.0)
0.079
(2.0)
0.079
(2.0)
0.110
(2.8)
0.030
(.76)
0.040
(1.0)
Gate
Gate
Gate
MT1 / Cathode
MT1
Not
used
M
T
2
SOT-223
Footprint
Dimensions are in inches (and millimeters).
MT2 / Anode
MT1 / Cathode
MT2 / Anode