Hardware design
SPSGRF
12/24
DocID027664 Rev 6
5 Hardware
design
The SPSGRF module supports SPI hardware interfaces.
Note:
- All unused pins should be left floating; do not ground.
- All GND pins must be well grounded.
- The area around the module should be free of any ground planes, power planes, trace
routings, or metal for 6 mm from the module antenna position, in all directions.
- Traces should not be routed underneath the module
5.1 Reflow
soldering
The SPSGRF is a surface mount sub-1 GHz transceiver module supplied on an 11 pin, 4-
layer PCB. The final assembly recommended reflow profiles are indicated below.
The soldering phase must be executed with care. In order to avoid an undesired melting
phenomenon, particular attention should be given to the setup of the peak temperature.
Table 10
provides suggestions for the temperature profile based on IPC/JEDEC J-STD-
020C, July 2004 recommendations.
Table 10. Soldering recommendations
Profile feature
PB-free assembly
Average ramp up rate (T
SMAX
to T
p
)
3°C/ sec max
Preheat
Temperature min (T
S
min)
150 °C
Temperature max (T
S
max)
200 °C
Time (t
S
min to t
S
max) (t
S
)
60-100 sec
Time maintained above:
Temperature T
L
217 °C
Time t
L
60-70 sec
Peak temperature (T
P
)
240 + 0 °C
Time within 5 °C of actual peak temperature (t
P
)
10-20 sec
Ramp down rate
6 °C/sec
Time from 25 °C to peak temperature
8 minutes max