12
Calibration
Calibration procedure is shown
in Figure 22. CoolPAM requires
two calibration tables for high
mode and low mode respectively.
This is due to gain difference in
each mode.
For continuous output power at
the points of mode change, the
input power should be adjusted
according to gain step during the
mode change.
Offset Value
(difference between
rising point and falling point)
Offset value, which is the differ-
ence between the rising point
(output power where PA mode
changes from low mode to high
mode) and falling point (output
power where PA mode changes
from high mode to low mode),
should be set to prevent system
oscillation. 3 to 5 dB is recom-
mended for Hysteresis.
Average Current & Talk Time
Probability Distribution Func-
tion implies that what is impor-
tant for longer talk time is the
efficiency of low or medium
power range rather than the
efficiency at full power. WS2512
idle current is 13 mA and operat-
ing current at 16 dBm is 54 mA
at nominal condition. Average
current calculated with CDMA
PDF is 26 mA in urban area and
43 mA in suburban area for
2-mode control. Average current
can be reduced with 3-mode
control, which results in 20 mA
in urban area and 38 mA in
suburban area. This PA with low
current consumption prolongs
talk time by no less than 30
minutes compared to other PAs.
Average current = ∫(PDF x Current)dp
Figure 22. Calibration procedure.
Figure 23. Setting of offset between rising and
falling power.
Figure 24. CDMA Power Distribution Function.
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
5.00
-50 -40 -30 -20 -10 0 10 20 30
PA Out (dBm)
CDG Urban
CDG Suburban
Conv PAM
Digitally Controlled PAM Cool PAM
0
100
200
300
500
400
600
700
PDF
CURRENT (mA)
Pou
Min PWR
Max PWR
High mode
TX AGC
Low mode
Rising
Falling
RisingFalling
High Mode
Low Mode
Pou
Gain
