Texas Instruments SWRU294, User Manual

Page: 17 / 57

SWRU294
Page 17/40
6.3.1 Battery Power
The SmartRF TrxEB includes a battery holder for two 1.5 V AA batteries on the reverse side of
the PCB. Normal AA batteries can be used and the onboard regulator supplies 3.3 V to the board.
The power source selection jumpers should short circuit pin 1-2
(“BATT”) and 9-10 (“LCL”) of
header P17, see Figure 7.
Figure 7
– P17 jumper settings to power TrxEB using batteries
The maximum current consumption is limited by the regulator to 800 mA.
6.3.2 USB Power
When the SmartRF TrxEB 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 board. The power source
selection jumpers should short circuit pin 3-4
(“USB”) and 9-10 (“LCL”) of header P17 (Figure 8).
Figure 8
– P17 jumper settings to power TrxEB via the USB cable
The maximum current consumption is limited by the regulator to 1500 mA
1
.
1
Note that most USB power sources are limited to 500 mA.