Sidactor Protection Thyristor Products Page 27 SIDACtor Protection Thyristor Products

SIDACtor Protection Thyristors 2017 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 02/23/17 Lead-Free Soldering Recommendations Littelfuse now offers only RoHS-compliant SIDACtor devices. This conversion requires a change from former Sn- Pb board-mounting process parameters for two reasons: The wettability (how well the molten solder flows on solderable surfaces) is degraded for Sn-Ag-Cu alloys (industry-preferred lead-free solder) as compared to Sn- Pb eutectics. The melting point for Sn-Ag-Cu alloys is typically around 220C (varying slightly among different alloys), much higher than the 183C melting point of conventional Sn- Pb eutectic solder. Increasing profile temperatures and/or dwell times typically overcomes these issues. This board-mounting standard serves as a design guideline for the electronics business unit relative to lead-free or RoHS-compliant product development across all Littelfuse facilities worldwide. This design guideline is applicable to all new product development programs as well as modifications of existing products. Table 1.3 Convection Reflow (SMD) Parameters and Lead-Free Requirement Convection Reflow - Surface Mount Devices (SMD) Table 1.3 defines the reflow parameter and lead-free requirements for convection reflow SMD soldering. Wave Solder - Through-Hole Devices (THD) Table 1.4 defines the wave parameter and lead-free requirements for THD wave soldering. Reflow Parameter Lead-Free Requirement Preheat (depending on flux only) Temperature Min Temperature Max Time (Min to Max) 150C 200C 60-180 seconds Solder Pot Temperature 245-265C (Max) Solder Dwell Time 2-3.5 seconds Cooling -6C/second (Max) Table 1.4 Wave Solder (THD) Parameters and Lead-Free Requirement Recommended Soldering Reflow Profile Time Temperature T P T L T S(max) T S(min) 25 t P t L t S time to peak temperature (t 25C to peak) Ramp-down Ramp-up Preheat Critical Zone T L to T P Figure 1 Reflow Condition Pb-Free assembly (see figure above) 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) 3C/sec. Max. T S(max) to T L - Ramp-up Rate 3C/sec. Max. Reflow - Temperature (T L ) (Liquidus) +217C - Temperature (t L ) 60-150 secs. Peak Temp (T P ) +260(+0/-5)C Time within 5C of actual Peak Temp (t p ) 30 secs. Max. Ramp-down Rate 6C/sec. Max. Time 25C to Peak Temp (T P ) 8 min. Max. Do not exceed +260C

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