AirGlow radio module integration guide
Version: 2 March 17, 2022
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www.lumenradio.com
Phone: +46 31 301 03 70
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Fax: +46 31 301 03 80
SE-416 68 Gothenburg
Sweden
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7.2
Battery backup considerations
The battery used in the RTC circuit is of a rechargeable type which is recommended for time
keeping during system power losses. Battery discharge time is highly dependent on ambient
temperature. Low temperatures will have a significant impact on battery capacity.
Below is an example of discharge time for the Seiko Instruments battery MS621T-FL11E used in
the RTC reference design.
Consumption
(RTC timekeeping mode)
0,7
µA
Ca25°C
3,5
mAh
Time to discharge
5000
hours
208
days
Capacity -40°C
1,2
mAh
Time to discharge
1714
hours
71
days
If the battery is discharged absolute time will be lost but absolute time will be set once the AirGlow
app is connected to any powered AirGlow module in the network.
8
Layout considerations
Electrical and mechanical design files are available for download at the LumenRadio online
support page for the AirGlow module.
8.1
Antenna
The antenna connector of the module is a u.FL type. The antenna shall have a characteristic
impedance of 50 ohm at 2.45GHz. See section 9.
“Recommended antennas” for more information.
8.2
AirGlow module PAD dimensions
All units in mm
Refer to the picture above
Oblong 1.4 x 2.79 (oblong edge a half circle with diameter 1.4)
Small rectangles left edge 1.0 x 0.8 (red)
Small squares right edge 1.02 x 1.02 (blue)
Large square 2.0 x 2.0 (green)
