ADL5571-EVALZ AD [Analog Devices], ADL5571-EVALZ Datasheet - Page 12

• Manufacturer Part Number: ADL5571-EVALZ
• Description: 2.5 GHz to 2.7 GHz WiMAX Power Amplifier
• Manufacturer: AD [Analog Devices]

ADL5571
64 QAM OFDMA PERFORMANCE
The ADL5571 shows exceptional performance when used with
a higher order modulation scheme, such as a 64 QAM system.
Figure 22, Figure 23, and Figure 24 illuminate the EVM, gain,
and current consumption performance within the context of a
64 QAM OFDMA system.
32
Figure 23. Gain vs. Frequency Performance at V
30
29
28
27
26
31
14
13
12
10
11
2500 2520 2540 2560 2580 2600 2620 2640 2660 2680 2700
9
8
7
6
5
4
3
2
1
0
8
Figure 22. EVM vs. P
10
12
2700MHz
64 QAM OFDMA Signal
64 QAM OFDMA Signal
14
FREQUENCY (MHz)
OUT
16
Performance at V
P
OUT
18
(dBm)
2500MHz
20
2600MHz
22
CC
= 3.3 V and
CC
24
= 3.3 V and
26
28
Rev. 0 | Page 12 of 16
POWER-ADDED EFFICIENCY
The efficiency of the ADL5571 is defined on the current that it
draws during the data burst of an 802.16e OFDMA signal. In
typical test setup, the average rms current, I
However,
where:
I
signal.
I
data burst and the device remains biased, the sleep current
(<1 μA) if the device is defaulted to sleep mode, or the standby
current.
For example, in a 31% duty cycle 802.16e OFDMA signal,
the burst current is calculated by rearranging the previous
equation to get
Finally, the PAE is calculated by
When RF is 2.6 GHz, 31% 16 QAM OFDMA signal,
V
Power is −4 dBm, the ADL5571 consumes a burst current,
I
BURST
DEFAULT
BURST
CC
is 3.3 V, RF Output Power is 25 dBm, and RF Input
I
(1 − Duty Cycle [in decimal]) × I
PAE
I
RF
AVG
is the rms current during the data burst of an OFDMA
is 450 mA and PAE = 21%.
BURST
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
can be the quiescent current drawn when there is no
0
= Duty Cycle (in decimal) × I
Output
Figure 24. Burst Current vs. P
0
(%)
=
(
=
Ι
2350 MHz, 31% 802.16e OFDMA Signal
AVG
5
Power
−
V
CC
0.69
0.31
(V)
(mW)
10
×
×
I
DEFAULT
P
I
OUT
−
BURST
RF
15
OUT
(dBm)
(mA)
at V
)
Input
DEFAULT
BURST
CC
20
= 3.3 V, 64 QAM,
Power
+
AVG
, is measured.
25
(mW)
30
×
100