GUIDELINE FOR AUTOMATED REFLOW SOLDERING PROCESS FOR DCO, DXO AND DBO SERIES OF VOLTAGE CONTROLLED OSCILLATORS Forward The guidelines provided in this application note comply with JEDC J-STD-020 and describe the basic surface-mounting assembly requirements for solder reflow of voltage controlled oscillators and synthesizers manufactured by Synergy Microwave Corporation. Optimum yields are achieved by careful optimization of the heating profile to allow for package size limitations. Peak Reflow Temperature Determining the maximum allowable peak reflow temperature is a process that involves consideration of the package volume and thickness for both SnPb and Pb-free soldering processes as described in Table I below: Table I. Package peak reflow temperature (Tp) Volume Reflow Process Thickness SnPb >2.5 mm 225oC +0/-5oC Pb-Free >2.5 mm 260oC +0/-5oC <350 mm3 tP Tp Critical Zone TL to TP Temperature Ramp-up TL tL Tsmax Ramp-down Tsmin tS Preheat 25oC t 25oC to Peak Time Figure 1. 1 of 3 Temperature reflow profile AN7302 Rev. A 01/13/15 Table II. Reflow profile parameters Reflow Profile Feature Average ramp-up rate (Tsmax to Tp) Preheat -Minimum Temperature (TSmin) -Maximum Temperature (TSmax) -Time (TSmin to TSmax) Time maintained above: -Minimum Temperature (TL) -Time (tL) Peak Temperature (Tp) Time within 5oC of actual peak temperature (tp) Ramp-down rate Time at 25oC to Peak Temperature SnPb Eutectic Assembly Pb-Free Assembly 3oC/second max. 3oC/second max. 100oC 150oC 60 – 120 seconds 150oC 200oC 60 – 180 seconds 183oC 60 – 150 seconds Per Table I 217oC 60 – 150 seconds Per Table I 10-30 seconds 20-40 seconds 6oC/second max. 6oC/second max. 6 minutes max. 8 minutes max. Consideration for maximum reflow temperature limits– One reflow pass All parts are soldered internally with solder having a reflow temperature melting point of 235 ºC. If the maximum reflow profile does not exceed 228 ºC, no special cooling precautions are required. In cases where the application requires the solder profile to exceed 228 ºC (Never to exceed 260 ºC!), care has to be taken so that the module will not be exposed to any vibration, as the molten solder can shift component placement. The molten solder must be allowed to solidify with no vibration until the device cools down to below 220 ºC. This allows for any residual heat trapped in the device to cool below the solder melting temperature, which is usually hotter inside the device. For technical assistance contact: Synergy Microwave Corporation 201 McLean Boulevard Paterson, NJ 07504 Tel. 973-881-8800 Fax 973-881-8361 Email: [email protected] 2 of 3 AN7302 Rev. A 01/13/15 - Recommended Solder Reflow profile for Pb-Free Process - 3 of 3 AN7302 Rev. A 01/13/15