Datasheet ADL5570 (Analog Devices) - 9

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ADL5570 64 QAM OFDMA PERFORMANCE 0.9
The ADL5570 shows exceptional performance when used with
0.8
a higher order modulation scheme, such as a 64 QAM system.
0.7
Figure 13, Figure 14, and Figure 15 illuminate the EVM, gain,
0.6
and current consumption performance within the context of
) A (
a 64 QAM OFDMA system.
0.5 NT E 19 0.4 18 CURR 17 0.3 16 15 2350MHz 0.2 14 13 0.1 12 ) 11 2400MHz 0 10 0 5 10 15 20 25 30 35
08 0
M (% 9
9- 72
EV P 8 OUT (dBm)
06
7
Figure 15. Burst Current vs. POUT at VCC = 3.5 V, 64 QAM,
6
2350 MHz, 31% 802.16e OFDMA Signal
5 4 3 2300MHz POWER-ADDED EFFICIENCY 2 1
The efficiency of the ADL5570 is defined on the current that it
0
draws during the data burst of an 802.16e OFDMA signal. In 06
0 5 10 15 20 25 30 35
0 9- 72
POUT (dBm)
typical test setup, the average rms current, IAVG, is measured. 06 Figure 13. EVM vs. P However, OUT Performance at VCC = 3.5 V and 64 QAM OFDMA Signal IAVG = Duty Cycle (in decimal) × IBURST +
32
(1 − Duty Cycle [in decimal]) × IDEFAULT where: I
31
BURST is the rms current during the data burst of an OFDMA signal.
)
IDEFAULT can be the quiescent current drawn when there is no
B d ( 30
data burst and the device remains biased, the sleep current
IN
(1 mA) if the device is defaulted to sleep mode, or the
GA
standby current.
29
For example, in a 31% duty cycle 802.16e OFDMA signal, the burst current is calculated by rearranging the previous equation to get
28 2280 2300 2320 2340 2360 2380 2400 2420
7 (Ι − 0.69× I ) -00 AVG DEFAULT = 29 I
FREQUENCY (MHz)
67 BURST 0 0.31 Figure 14. Gain vs. Frequency Performance at V Finally, the PAE is calculated by CC = 3.5 V and 64 QAM OFDMA Signal RF Output Power (mW) − RF Input Power (mW) PAE (%) = × 100 V (V) × I (mA) CC BURST When RF = 2.35 GHz, 31% 16 QAM OFDMA signal, VCC = 3.5 V, RF output power = 25 dBm, and RF input power = −4 dBm, the ADL5570 consumes a burst current, IBURST = 450 mA and PAE = 21%. Rev. 0 | Page 9 of 12 Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS VCC = 3.5 V ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS APPLICATIONS BASIC CONNECTIONS Power Supply RF Input Interface RF Output Interface Transmit/Standby Enable VREG Enable MODE High Power/Low Power Enable 64 QAM OFDMA PERFORMANCE POWER-ADDED EFFICIENCY EVALUATION BOARD MEASUREMENT SETUP USING THE ADL5570 EVALUATION BOARD OUTLINE DIMENSIONS ORDERING GUIDE