114-13290
5 of 10
Rev A
Figure 5
No flux allowable on any of the four inner pads.
B. Connectors with SMT Contacts
1. Solderability
The pc board pads must be solderable in accordance with Test Specification 109-11 (Test Method A,
non-activated rosin flux) and all other requirements for surface mount contacts specified in this document.
2. Solder Paste Characteristics
1. Alloy type shall be SAC 305; Sn 96.5/Ag 3.0/Cu 0.5.
2.Flux incorporated in the paste shall be rosin, mildly active (RMA) type.
3.Paste will be at least 80% solids by volume.
4.Mesh designation -200 to +325 (74 to 44 square micron openings, respectively).
5.Minimum viscosity of screen print shall be 5y10% cp (centipoise) .
6.Minimum viscosity of stencil print shall be 7.5y10% cp (centipoise).
3. Solder Volume
Solder volume may vary depending on solder paste composition.
Solder volume is required to be 4.27 mm3 per solder foot (calculated per 50% solid content).
4. Screen (or Stencil)
The stencil aperture shall be determined by the circuit pad size and thickness. It may be any shape as long
as it prevents solder bridg ing and maintains the given volume of solder paste.
C. Process
Connectors with surface mount contacts should be soldered using vapor phase (VPR), double-sided, non-
focused infrared reflow (I R) or equivalent soldering techniques. Due to many variables involved with the
reflow process (i.e., component density, orientation, etc.), it is recommended that trial runs be conducted
under actual manufacturing conditions to ensure product and process compatibility. These connectors will
withstand the temperature and exposure time specified in Figure 6.
Figure 6
The lead-free reflow profile is shown in Figure 7.
‡Alpha and Kester are trademarks.
FLUX TYPE ACTIVITY RESIDUE COMMERCIAL DESIGNATION
KESTER‡ ALPHA‡
Type RMA (Mildly Activated) Mild Noncorrosive 185/197 611
SOLDERING PROCESS TEMPERATURE (Max) TIME (At Max Temperature)
IR 220°C [428°F] 3 Minutes