ADL5390-EVALZ Analog Devices Inc, ADL5390-EVALZ Datasheet - Page 17

• Manufacturer Part Number: ADL5390-EVALZ
• Manufacturer: Analog Devices Inc

Specifications of ADL5390-EVALZ

• Lead Free Status / Rohs Status: Compliant

QUADRATURE MODULATOR
The ADL5390 can be used as a quadrature modulator by driving
the RF I and Q inputs (INPI and INPQ) single-ended through a
90
applied to the baseband I and Q gain control inputs (IBBP/IBBM
and QBBP/QBBM). A simplified schematic is shown in Figure
38.
LO IN
Single sideband performance of a quadrature modulator is
determined by the magnitude and phase balance (compared to
a 90
Because the ADL5390 has matched amplifiers and mixers in
the I and Q channel, most of the single sideband performance
will be determined by the external 90
single sideband performance can be achieved by choosing a
well-balanced 90
differences in the 90
the magnitude and phase of the I and Q data. Figure 39 shows
the performance of the ADL5390 used in conjunction with Mini-
Circuits QCN-12 90
sideband improvement as the I and Q data is adjusted in magnitude
and phase to achieve better single sideband performance.
For maximum dynamic range, the ADL5390 should be driven
as close to the output 1 dB compression point as possible. The
output power of the ADL5390 increases linearly with the RF
(LO) input power and baseband gain control input voltage until
the ADL5390 reaches compression. At the 1 dB compression
point, the lower sideband starts to increase. Figure 41 demon-
strates the output spectrum of a 3-carrier CDMA2000 signal
applied to the I/Q baseband gain control inputs. As the RF (LO)
power is increased, the relative amount of noise is reduced until
the ADL5390 goes into compression. At this point, the relative
noise increases, as shown in Figure 42.
Analog Devices has several quadrature/vector modulators that
have highly accurate integrated 90
AD8341, AD8345, AD8346, AD8349—that cover a variety of
frequency bands.
50Ω
o
phase splitter to serve as the LO input. I/Q modulation is
o
offset) at the summation point of the I and Q signals.
SUM
PORT
TERM
PORT
90° PHASE
SPLITTER
QCN-12
Figure 38. Quadrature Modulator Application
PORT 1
PORT 2
o
phase splitter. However, phase and magnitude
o
o
66.5Ω
66.5Ω
phase splitter can be corrected by adjusting
10nF
10nF
power splitter. Figure 40 shows the single
INPI
INPQ
ADL5390
Q DATA
I DATA
o
phase splitters—AD8340,
o
phase splitter. Good
RFOM
RFOP
10nF
10nF
(M/A-COM)
ETC1-1-13
1
3
5
4
ROFP
Rev. 0 | Page 17 of 24
Figure 40. SSB Modulator Applications with Gain and Phase Errors Corrected,
RF Pin = −15 dBm, VIBB = VQBB = 0.5 V (With Reference to a Common-Mode
Figure 39. SSB Quadrature Modulator Result Using External 90° Phase Splitter,
Voltage of 0.5 V), I/Q Phase Offset by 3
1 AP
CLRWR
1 AP
CLRWR
–10
–20
–30
–40
–50
–60
–70
–10
–20
–30
–40
–50
–60
–70
–80
–90
0
0
(With Reference to a Common-Mode Voltage of 0.5 V)
CENTER 900MHz
CENTER 900MHz
REF 7dBm
REF 7dBm
DESIRED SIDEBAND
–16.20dBm
900.998397436MHz
UNDESIRED SIDEBAND
–23.27dB
–1.996794872MHz
THIRD BASEBAND HARMONIC
–37.38dB
–4.004807692MHz
LO FEEDTHROUGH
–41.27dB
–998.397435897kHz
-80
-90
DESIRED SIDEBAND
–16.78dBm
900.998397436MHz
UNDESIRED SIDEBAND
–51.81dB
–1.996794872MHz
THIRD BASEBAND HARMONIC
–38.45dB
–4.004807692MHz
LO FEEDTHROUGH
–41.49dB
–998.397435897kHz
3
3
RF P
IN
= −15 dBm, VIBB = VQBB = 0.5 V
2
2
ATT 35dB
ATT 35dB
700kHz/
700kHz/
4
o
4
, and Magnitude Offset by 0.5 V
*
*
RBW 3kHz
VWB 10kHz
SWT 780ms
RBW 3kHz
VWB 10kHz
SWT 780ms
1
1
SPAN 7MHz
SPAN 7MHz
ADL5390
A
A