
Application Notes
AN1004
2002 Teccor Electronics
Thyristor Product Catalog
AN1004 - 5
http://www.teccor.com
+1 972-580-7777
Soldering Of Leads
A prime consideration in soldering leads is the soldering of 
device leads into PC boards, heat sinks, and so on. Significant 
damage can be done to the device through improper soldering. In 
any soldering process, do not exceed the data sheet lead solder 
temperature of +230
 °
C for 10 seconds, maximum, 
≥
1/16" from 
the case.
This application note presents details about the following three 
types of soldering:
Hand soldering
Wave soldering
Dip soldering
Hand Soldering
This method is mostly used in prototype breadboarding applica-
tions and production of small modules. It has the greatest poten-
tial for misuse. The following recommendations apply to Teccor 
TO-92, TO-202, TO-220, and TO-218 packages.
Select a small- to medium-duty electric soldering iron of 25 W to 
45 W designed for electrical assembly application. Tip tempera-
ture should be rated from 600 °F to 800 °F (300 °C to 425 °C). 
The iron should have sufficient heat capacity to heat the joint 
quickly and efficiently in order to minimize contact time to the 
part. Pencil tip probes work very well. Neither heavy-duty electri-
cal irons of greater than 45 W nor flame-heated irons and large 
heavy tips are recommended, as the tip temperatures are far too 
high and uncontrollable and can easily exceed the time-tempera-
ture limit of the part.
Teccor Fastpak devices require a different soldering technique. 
Circuit connection can be done by either quick-connect terminals 
or solder.
Since most quick-connect 0.250” female terminals have a maxi-
mum rating of 30 A, connection to terminals should be made by 
soldering wires instead of quick-connects.
Recommended wire is 10 AWG stranded wire for use with MT1 
and MT2 for load currents above 30 A. Soldering should be per-
formed with a 100-watt soldering iron. The iron should not remain 
in contact with the wire and terminal longer than 40 seconds so 
the Fastpak triac is not damaged.
For the Teccor TO-218X package, the basic rules for hand sol-
dering apply; however, a larger iron may be required to apply suf-
ficient heat to the larger leads to efficiently solder the joint.
Remember not to exceed the lead solder temperatures of 
+230 °C for 10 seconds, maximum, 
≥
1/16" (1.59mm) from the 
case.
A 60/40 or 63/37 Sn/Pb solder is acceptable. This low melting-
point solder, used in conjunction with a mildly activated rosin flux, 
is recommended.
Insert the device into the PC board and, if required, attach the 
device to the heat sink before soldering. Each lead should be 
individually heat sinked as it is soldered. Commercially available 
heat sink clips are excellent for this use. Hemostats may also be 
used if available. Needle-nose pliers are a good heat sink choice; 
however, they are not as handy as stand-alone type clips.
In any case, the lead should be clipped or grasped between the 
solder joint and the case, as near to the joint as possible. Avoid 
straining or twisting the lead in any way.
Use a clean pre-tinned iron, and solder the joint as quickly as 
possible. Avoid overheating the joint or bringing the iron or solder 
into contact with other leads that are not heat sinked.
Wave Solder
Wave soldering is one of the most efficient methods of soldering 
large numbers of PC boards quickly and effectively. Guidelines 
for soldering by this method are supplied by equipment manufac-
turers. The boards should be pre-heated to avoid thermal shock 
to semiconductor components, and the time-temperature cycle in 
the solder wave should be regulated to avoid heating the device 
beyond the recommended temperature rating. A mildly activated 
resin flux is recommended. Figure AN1004.12 shows typical heat 
and time conditions.
Figure AN1004.12
Reflow Soldering with Pre-heating
Dip Soldering
Dip soldering is very similar to wave soldering, but it is a hand 
operation. Follow the same considerations as for wave soldering, 
particularly the time-temperature cycle which may become oper-
ator dependent because of the wide process variations that may 
occur. This method is not recommended.
Board or device clean-up is left to the discretion of the customer. 
Teccor devices are tolerant of a wide variety of solvents, and they 
conform to MIL-STD 202E method 215 “Resistance to Solvents.”
Time  (Seconds)
0
0
20
40
60
80
100
120
140
160
180
200
220
240
30
60
90
120
150
180
210
240
270
300
T
Pre-heat
Soak
Reflow
Cool
Down
0.5 - 0.6 
C/s
1.3 - 1.6 
C/s
<2.5 
C/s
<2.5 
C/s
Peak Temperature
220 
C - 245 
C
Soaking Zone
Reflow Zone
Pre-heating Zone
( 2-4 min MAX )
( 2 min. MAX )
60 - 90 s typical
( 2 min. MAX )
30 - 60 s typical
260