User's Manual

Page 24 of 28 A85xxE24A91 – Users Manual
Release Date: Dec 1
st
2010
• Add decoupling capacitance to pin 33 (AVdd), 1uF to 2.2uF ceramic capacitor is
suggested (do not use Tantalum).
• Add a low noise LDO in the supply line to pin 33 (AVdd) (the TPS731xx low Dropout
Regulator from TI is recommended).
Note that if operated from a battery source there is no need for additional noise reduction. Also
note that if the noise source can be synchronized to be off whenever the module is transmitting
or receiving (using XPAEN and XLNAEN) then that will also suffice.
5. Configuration and Programming
The integrator of this module into an application must program the module to match both the
Codec chip used and the human interface methods employed. To do this the integrator must
use the PurePath™ software from Texas Instruments to configure the module
5.1. Calibrating Transmit Power
This power calibration number is an approximate power output value in dBm for the CC85xx
chip – however the modules CC2591 adds an additional 16dB amplification.
The maximum allowed setting to comply with FCC/IC is “0” (which produces 16dBm
output power). Any setting above this voids the end users right to use the equipment.
It can be useful to set a lower power for systems that do not require the full range and thus save
on power consumption. The typical power consumption at 3.3v supply for a A8520E24A91
module is shown below depending on the output power setting.
Output
Power
Setting
Actual Output
Power
(Approximate)
Current Consumption [mA] @ 3.3V
AVdd,IOVdd, Ambient
# [dBm] Master Slave
0 16 48 18
-1 15 43 18
-2 14 39 17
-3 13 38 17
-4 12 34 16
-5 11 33 16
-6 10 32 15
-7 9 32 15
-8 8 30 15
-9 7 28 15
-10 6 27 15
In the PurePath
TM
configurator when creating the application image, in the “Radio” page for both
master and slave the target Tx power must be set to 0 dBm, or lower, (note that this produces
16dBm peak from the module due to CC2591 PA/LNA):