User’s Guide
SWRU321A
– May 2013
Page 15/32
Figure 8
– Main power switch (P501) and source selection switch (P502)
6.2.1 USB Power
When the SmartRF06EB is connected to a PC via a USB cable, it can draw power from the USB
bus. The onboard voltage regulator supplies approximately 3.3 V to the mounted EM and the EB
peripherals. To power the mounted EM and the EB peripherals from the USB bus, the power
source selection switch (S502) s
hould be in “USB” position (Figure 9).
The maximum current consumption is limited by the regulator to 1500 mA
3
.
Figure 9
– SmartRF06EB power selection switch (P502) in “USB” position
6.2.2 Battery Power
The SmartRF06EB can be powered using two 1.5 V AAA alkaline batteries or a 3 V CR2032 coin
cell battery. The battery holders for the AAA batteries and the CR2032 coin cell battery are
located on the reverse side of the PCB. To power the mounted EM and the EB peripherals using
batteries, the power source selection switch (S502) should be in “BAT” position (Figure 10).
When battery powered, the EM power domain is by default regulated to 2.1 V. The voltage
regulator may be bypassed by mounting a jumper on J502. See section 6.3.2 for more details.
Do not power the SmartRF06EB using two 1.5 V AAA batteries and a 3 V CR2032
coin cell battery at the same time. Doing so may lead to excessive currents that may
damage the batteries or cause onboard components to break.
3
Note that most USB power sources are limited to 500 mA.