Thyristor Semiconductor Products Page 42 Thyristor

2014 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 12/14/14 Teccor brand Thyristors AN1004 maximum 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. Solderingshould be performed 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 Littelfuse TO-218X package, the basic rules for hand soldering apply; however, a larger iron may be required to apply sufficient heat to the larger leads to efficiently solder the joint. Remember not to exceed the lead solder temperatures of 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 manufacturers. 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. Figures AN1004.12 and .13 show typical heat and time conditions. Time Temperature T P T L T S(max) T S(min) 25 t P t L t S time to peak temperature Preheat Ramp-up Ramp-down Ramp-do Figure AN1004.12 Reflow Soldering with Pre-heating Reflow Condition Pb - Free assembly Pre Heat - Temperature Min (T s(min) ) 150C - Temperature Max (T s(max) ) 200C - Time (min to max) (t s ) 60 - 180 secs Average ramp up rate (Liquidus Temp (T L ) to peak 5C/second max T S(max) to T L - Ramp-up Rate 5C/second max Reflow - Temperature (T L ) (Liquidus) 217C - Time (min to max) (t s ) 60 - 150 seconds Peak Temperature (T P ) 260 +0/-5 C Time within 5C of actual peak Temperature (t p ) 20 - 40 seconds Ramp-down Rate 5C/second max Time 25C to peak Temperature (T P ) 8 minutes Max. Do not exceed 280C 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 operator 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. Littelfuse devices are tolerant of a wide variety of solvents, and they conform to MIL-STD 202E method Figure AN1004.13 Heat and Time Table Mounting and Handling of Semiconductor Devices (continued)

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