This chapter contains information about the recommended reflow profile and solder paste for circuit board assembly using aQFN73™.
Type 4 solder paste (25 to 45 micron particle size range) or finer should be used for solder printing. Senju M705-S101-S4 is a recommended solder paste. The following diagram shows the reflow profile for SAC305 solder paste, which is commonly used:
Figure 1. Reflow profile
The following table shows typical temperatures and ramp-up rates for the aQFN™ package's reflow soldering profile:
| Profile feature | Specification | Temperature °C |
|---|---|---|
| Ramp-up rate | <1.2°C/s | 25~150 |
| Preheat time | 60~90 s | 155~165 |
| Ramp-up | <1°C/s | 200~ peak |
| Reflow time | 60~90 s | Above 220 |
| Peak | - | 230~255 |
| Cooling rate | <6°C/s | 25~ peak |