u-blox LEA-5 Series Hardware Manual

Contents

u-blox LEA-5 Series Hardware Manual Manual pdf 53 page image

LEA-5, NEO-5, TIM-5H - Hardware Integration ManualGPS.G5-MS5-09027-A2 Released Handling and solderingPage 53 of 68The final soldering temperature chosen at the factory depends on additional external factors like choice ofsoldering paste, size, thickness and properties of the base board, etc. Exceeding the maximum solderingtemperature in the recommended soldering profile may permanently damage the module.Preheat0 50 100 150 200 250 30050100150200250Heating Cooling50100150200250max 1- 4 °C/smax 60 - 120 sPeak Temp.230 - 250 °CLiquidus Temperature216 - 221[°C]Elapsed Time [s]max 20 - 40 sTypical LeadfreeSoldering ProfileEnd Temp.150 - 200 °Cmax 3 °C/s[°C]Figure 45: Recommended soldering profileWhen soldering u-blox 5 modules in a leaded process, check the following temperatures:o PB- Technology Soaktime: 40-80seco Time above Liquidus: 40-90 seco Peak temperature: 225-235 °Cu-blox 5 modules must not be soldered with a damp heat process.3.3.3 Optical inspectionAfter soldering the u-blox 5 module, consider an optical inspection step to check whether:The module is properly aligned and centered over the padsAll pads are properly solderedNo excess solder has created contacts to neighboring pads, or possibly to pad stacks and vias nearby.3.3.4 CleaningIn general, cleaning the populated modules is strongly discouraged. Residues underneath the modules cannot beeasily removed with a washing process.Cleaning with water will lead to capillary effects where water is absorbed in the gap between the baseboardand the module. The combination of residues of soldering flux and encapsulated water leads to shortcircuits or resistor-like interconnections between neighboring pads.Cleaning with alcohol or other organic solvents can result in soldering flux residues flooding into the twohousings, areas that are not accessible for post-wash inspections. The solvent will also damage the stickerand the ink-jet printed text.Ultrasonic cleaning will permanently damage the module, in particular the quartz oscillators.The best approach is to use a "n“ clean" ”oldering paste and eliminate the cleaning step after the soldering.