Matched pair of multiplying VGAs
Broad frequency range 20 MHz to 2.4 GHz
Continuous magnitude control from +5 dB to −30 dB
Output third-order intercept 24 dBm
Output 1 dB compression point 11 dBm
Output noise floor −148 dBm/Hz
Adjustable modulation bandwidth up to 230 MHz
Fast output power disable
Single-supply voltage 4.75 V to 5.25 V
APPLICATIONS
PA linearization and predistortion
Amplitude and phase modulation
Variable matched attenuator and/or phase shifter
Cellular base stations
Radio links
Fixed wireless access
Broadband/CATV
RF/IF analog multiplexer
RF/IF Vector Multiplier
ADL5390
FUNCTIONAL BLOCK DIAGRAM
VPRF
INMQ
INPQ
CMRF
INPI
INMI
CMOP
Figure 1.
VPS2OBBMQBBP
RFOP
RFOM
DSOPIBBMIBBP
04954-001
GENERAL DESCRIPTION
The ADL5390 vector multiplier consists of a matched pair of
broadband variable gain amplifiers whose outputs are summed.
The separate gain controls for each amplifier are linear-inmagnitude. If the two input RF signals are in quadrature, the
vector multiplier can be configured as a vector modulator or as
a variable attenuator/phase shifter by using the gain control pins
as Cartesian variables. In this case, the output amplitude can be
controlled from a maximum of +5 dB to less than –30 dB, and
the phase can be shifted continuously over the entire 360°
range. Since the signal paths are linear, the original modulation
on the inputs is preserved. If the two signals are independent,
then the vector multiplier can function as a 2:1 multiplexer or
can provide fading from one channel to another.
The ADL5390 operates over a wide frequency range of 20 MHz
to 2400 MHz. For a maximum gain setting on one channel at
380 MHz, the ADL5390 delivers an OP1dB of 11 dBm, an OIP3
of 24 dBm, and an output noise floor of −148 dBm/Hz. The gain
and phase matching between the two VGAs is better than 0.5 dB
and 1°, respectively, over most of the operating range.
The gain control inputs are dc-coupled with a +/−500 mV differential full-scale range centered about a 500 mV common
mode. The maximum modulation bandwidth is 230 MHz,
which can be reduced by adding external capacitors to limit the
noise bandwidth on the control lines.
Both the RF inputs and outputs can be used differentially or
single-ended and must be ac-coupled. The impedance of each
VGA RF input is 250 Ω to ground, and the differential output
impedance is nominally 50 Ω over the operating frequency
range. The DSOP pin allows the output stage to be disabled
quickly to protect subsequent stages from overdrive. The
ADL5390 operates off supply voltages from 4.75 V to 5.25 V
while consuming 135 mA.
The ADL5390 is fabricated on Analog Devices’ proprietary,
high performance 25 GHz SOI complementary bipolar IC
process. It is available in a 24-lead, Pb-free CSP package and
operates over a −40°C to +85°C temperature range. Evaluation
boards are available.
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Anal og Devices. Trademarks and
registered trademarks are the property of their respective owners.
VS = 5 V, TA = 25°C, ZO = 50 Ω, FRF = 380 MHz, single-ended source drive to INPI and INPQ, and INMI and INMQ are ac-coupled to
common, unless otherwise noted. 66.5 Ω termination resistors before ac-coupling capacitors on INPI and INPQ. The specifications refer
to one active channel with the other channel input terminated in 50 Ω. The common-mode level for the gain control inputs is 0.5 V. A
maximum gain setpoint of 1.0 refers to a differential gain control voltage of 0.5 V.
Table 1.
Parameter Conditions Min Typ Max Unit
OVERALL FUNCTION
Frequency Range
Gain Control Range Relative to maximum gain 35 dB
GAIN CONTROL INTERFACE (I and Q) QBBP, QBBM, IBBM, IBBP (Pins 4, 5, 14, 15)
Gain Scaling 3.5 1/V
Modulation Bandwidth
Second Harmonic Distortion
Third Harmonic Distortion
Step Response For gain from −15 dB to +5 dB 45 ns
For gain from +5 dB to −15 dB 47 ns
FRF = 70 MHz
Maximum Gain Maximum gain setpoint 4.6 dB
Gain Conformance Over gain setpoint of 0.2 to 1.0 0.25 dB
Output Noise Floor Maximum gain setpoint, no RF input −149 dBm/Hz
RF PIN = −5 dBm, frequency offset = 20 MHz −146 dBm/Hz
Output IP3
Output 1 dB Compression Point Maximum gain setpoint 10.7 dBm
Input 1 dB Compression Point Gain setpoint = 0.1 6.7 dBm
Gain Flatness Over any 60 MHz bandwidth 0.25 dB
Gain Matching At maximum gain setpoint 0.5 dB
Phase Matching At maximum gain setpoint ±0.25 Degrees
Input Impedance INPI, INMI, INMQ, INMP (Pins 20, 21, 22, 23)
Output Return Loss
FRF = 140 MHz
Maximum Gain Maximum gain setpoint 4.5 dB
Gain Conformance Over gain setpoint of 0.2 to 1.0 0.25 dB
Output Noise Floor Maximum gain setpoint, no RF input −144 dBm/Hz
RF PIN = −5 dBm, frequency offset = 20 MHz −145 dBm/Hz
Output IP3
Output 1 dB Compression Point Maximum gain setpoint 11 dBm
Input 1 dB Compression Point Gain setpoint = 0.1 7.1 dBm
Gain Flatness Over any 60 MHz bandwidth 0.25 dB
Gain Matching At maximum gain setpoint 0.5 dB
Phase Matching At maximum gain setpoint ±0.25 Degrees
Input Impedance INPI, INMI, INMQ, INMP (Pins 20, 21, 22, 23)
Output Return Loss
FRF = 380 MHz
Maximum Gain Maximum gain setpoint 4.1 dB
Gain Conformance Over gain setpoint of 0.2 to 1.0 0.25 dB
Output Noise Floor Maximum gain setpoint, no RF input −147.5 dBm/Hz
RF PIN = −5 dBm, frequency offset = 20 MHz −146 dBm/Hz
Output IP3
= 380 MHz, F
F
RF1
= 382.5 MHz, maximum
RF2
gain setpoint
Output 1 dB Compression Point Maximum gain setpoint 11.3 dBm
Input 1 dB Compression Point Gain setpoint = 0.1 8.3 dBm
Gain Flatness Over any 60 MHz bandwidth 0.25 dB
Gain Matching At maximum gain setpoint 0.5 dB
Phase Matching At maximum gain setpoint ±0.5 Degrees
Input Impedance INPI, INMI, INMQ, INMP (Pins 20, 21, 22, 23)
Output Return Loss
RFOP, RFOM (Pins 9, 10) measured through
balun
FRF = 900 MHz
Maximum Gain Maximum gain setpoint 4.5 dB
Gain Conformance Over gain setpoint of 0.2 to 1.0 0.4 dB
Output Noise Floor Maximum gain setpoint, no RF input −149.5 dBm/Hz
RF PIN = −5 dBm, frequency offset = 20 MHz −148 dBm/Hz
Output IP3
= 900 MHz, F
F
RF1
= 902.5 MHz, maximum
RF2
gain setpoint
Output 1 dB Compression Point Maximum gain setpoint 11.5 dBm
Input 1 dB Compression Point Gain setpoint = 0.1 8.5 dBm
Gain Flatness Over any 60 MHz bandwidth 0.25 dB
Gain Matching At maximum gain setpoint 0.6 dB
Phase Matching At maximum gain setpoint ±1 Degrees
Input Impedance INPI, INMI, INMQ, INMP (Pins 20, 21, 22, 23)
Output Return Loss
RFOP, RFOM (Pins 9, 10) measured through
balun
FRF = 2400 MHz
Maximum Gain Maximum gain setpoint 7.0 dB
Gain Conformance Over gain setpoint of 0.2 to 1.0 0.5 dB
Output Noise Floor Maximum gain setpoint, no RF input −147 dBm/Hz
RF PIN = −5 dBm, frequency offset = 20 MHz −144 dBm/Hz
Output IP3
= 2400 MHz, F
F
RF1
= 2402.5 MHz, maximum
RF2
gain setpoint
Output 1 dB Compression Point Maximum gain setpoint 9.6 dBm
Input 1 dB Compression Point Gain setpoint = 0.1 4.3 dBm
Gain Flatness Over any 60 MHz bandwidth 0.25 dB
Gain Matching At maximum gain setpoint 0.8 dB
Phase Matching At maximum gain setpoint ±2.5 Degrees
Input Impedance INPI, INMI, INMQ, INMP (Pins 20, 21, 22, 23)
Disable Threshold 2.5 V
Maximum Attenuation DSOP = 5 V 40 dB
Enable Response Time
Delay following high-to-low transition until
device meets full specifications
Disable Response Time
Delay following low-to-high transition until
device produces full attenuation
24.2 dBm
200||1
Ohms||pF
8.5 dB
23.3 dBm
180||0.6
Ohms||pF
6.8 dB
18.7 dBm
140||0.5
Ohms||pF
13.5 dB
15 ns
10 ns
Rev. 0 | Page 4 of 24
Page 5
ADL5390
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameters Rating
Supply Voltage VPRF, VPS2 5.5 V
DSOP 5.5 V
IBBP, IBBM, QBBP, QBBM 2.5 V
RFOP, RFOM 5.5 V
RF Input Power at Maximum Gain 10 dBm for 50 Ω
(INPI or INPQ, Single-Ended Drive)
Equivalent Voltage 2.0 V p-p
Internal Power Dissipation 825 mW
θJA (With Pad Soldered to Board) 59°C/W
Maximum Junction Temperature 125°C
Operating Temperature Range −40°C to +85°C
Storage Temperature Range −65°C to +150°C
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the
human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
Rev. 0 | Page 5 of 24
Page 6
ADL5390
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
CMRF
INPQ
INMQ
INMI
INPI
24
23 22 21 20 19
CMRF
VPRF
QFLP
QFLM
QBBP
QBBM
VPS2
1
2
3
4
5
6
ADL5390
TOP VIEW
(Not to Scale)
7 8 9 101112
RFOP
CMOP
CMOP
RFOM
CMOP
CMOP
18
VPRF
17
IFLP
16
IFLM
15
IBBP
14
IBBM
13
DSOP
04954-002
Figure 2. LFCSP Pin Configuration
Table 3. Pin Function Descriptions
Pin No. Mnemonic Description
2, 3 QFLP, QFLM
Q Baseband Input Filter Pins. Connect optional capacitor to reduce Q baseband gain control channel low-
pass corner frequency.
4, 5 QBBP, QBBM Q Channel Differential Baseband Gain Control Inputs. Typical common-mode bias level of 0.5 V.
6, 1, 18 VPS2, VPRF Positive Supply Voltage. VP of 4.75 V to 5.25 V.
7, 8, 11, 12,
CMOP, CMRF Device Common. Connect via lowest possible impedance to external circuit common.
19, 24
9, 10 RFOP, RFOM
Differential RF Outputs. Must be ac-coupled. Differential impedance 50 Ω nominal.
13 DSOP Output Disable. Pull high to disable output stage. Connect to common for normal operation.
14, 15 IBBM, IBBP I Channel Differential Baseband Gain Control Inputs. Typical common-mode bias level of 0.5 V.
16, 17 IFLM, IFLP
I Baseband Input Filter Pins. Connect optional capacitor to reduce I baseband gain control channel lowpass corner frequency.
20, 21 INPI, INMI
I Channel Differential RF Inputs. Must be ac-coupled. 250 Ω impedance to common on each pin. These
inputs can be driven single-ended without any performance degradation.
22, 23 INMQ, INPQ
Q Channel Differential RF Inputs. Must be ac-coupled. 250 Ω impedance to common on each pin. These
inputs can be driven single-ended without any performance degradation.
Exposed
Paddle
GND
The exposed paddle on the underside of the package should be soldered to a low thermal and electrical
impedance ground plane.
Rev. 0 | Page 6 of 24
Page 7
ADL5390
TYPICAL PERFORMANCE CHARACTERISTICS
10
5
0
–5
–10
GAIN (dB)
–15
–20
–25
–30
0.250
0.50
GAIN SETPOINT
FRF = 70MHz
= 140MHz
F
RF
= 380MHz
F
RF
= 900MHz
F
RF
= 2400MHz
F
RF
0.751.00
04954-003
5
4
3
2
1
0
–1
–2
CHANNEL GAIN MATCH (dB)
–3
–4
–5
03006009001200 1500 1800 2100 2400
+3
σ
–3
σ
FREQUENCY (MHz)
04954-006
Figure 3. Gain Magnitude vs. Gain Setpoint, RF Frequency = 70 MHz,
140 MHz, 380 MHz, 900 MHz, 2400 MHz (Channel I or Channel Q)
10
–5
–10
GAIN (dB)
–15
–20
–25
–30
TEMP = –40°C
TEMP = +25°C
5
TEMP = +85°C
0
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
GAIN SETPOINT
04954-004
Figure 4. Gain Magnitude vs. Gain Setpoint, Temp = +85°C, +25°C, −40°C,
RF Frequency = 380 MHz (Channel I or Channel Q)
4
+3σ= DASH LINE
σ
= SOLID LINE
–3
3
2
1
0
–1
GAIN ERROR (dB)
–2
–3
–4
00.250.500.751.0
GAIN SETPOINT
FRF = 70MHz
FRF = 140MHz
F
= 380MHz
RF
= 900MHz
F
RF
F
= 2400MHz
RF
04954-005
Figure 5. Gain Conformance Error vs. Gain Setpoint, RF Frequency = 70 MHz,
140 MHz, 380 MHz, 900 MHz, 2400 MHz
Figure 6. Channel Gain Matching (I to Q) vs. RF Frequency,
Gain Setpoint = 1.0
9
8
7
6
5
4
GAIN (dB)
3
2
1
0
03006009001200 1500 1800 2100 2400
FREQUENCY (MHz)
TEMP = –40°C
TEMP = +25°C
TEMP = +85°C
04954-007
Figure 7. Channel Gain vs. RF Frequency, Temp = +85°C, +25°C, −40°C,
Gain Setpoint = 1.0
5
+3σ= DASH LINE
σ
= SOLID LINE
–3
0
–5
–10
PHASE ERROR (Degrees)
–15
–20
00.250.500.751.0
GAIN SETPOINT
FRF = 70MHz
= 140MHz
F
RF
F
= 380MHz
RF
= 900MHz
F
RF
= 2400MHz
F
RF
04954-008
Figure 8. Single-Channel Phase Deviation vs. Gain Setpoint, Normalized to
Gain Setpoint = 1.0, RF Frequency = 70 MHz, 140 MHz, 380 MHz,
900 MHz, 2400 MHz
Rev. 0 | Page 7 of 24
Page 8
ADL5390
25
20
15
10
–5
–10
PHASE DIFFERRENCE (Degrees)
–15
–20
Figure 9. Channel-to-Channel Phase Matching vs. Gain Setpoint,
Figure 21. S11 of RF Input (Shunt R/C Representation)
SHUNT CAPACITANCE (pF)
SHUNT RESISTANCE (Ω)
F
(MHz)
RF
1.25
1.00
0.75
0.50
0.25
0
INPUT SHUNT CAPACITANCE (pF)
04954-021
0
–5
–10
–15
–20
–25
–30
–35
–40
–45
–50
RF OUTPUT POWER (dBm)
–55
–60
–65
–70
–75
00.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.55.0
DSOP VOLTAGE (V)
Figure 24. Power Shutdown Attenuation, RF = 380 MHz
04954-024
ADL5390 SDD22
90
60
30
330
300
)
I
150
→
|GRIDZ|
S
11TERMANG
I
210
IMPEDANCE CIRCLE
SDD22 NOM WFR DUT 1
S22 NOM WFR
120
240
10MHz
ARG(
GRIDZ
2.7GHz
10MHz
270
), RADS(S
3GHz
11
TERMANG
Figure 22. S22 of RF Output (Differential and Single-Ended through Balun)
139
138
Vp = 5.25
1
0
0180
04954-022
TEK RUN ENVELOPE12 AUG 04 16:48:01
1
CH1 500mV Ω
CH3 2.0V Ω D
S
M 10.0ns 5.0GS/s ET 200ps/pt
A CH3 760mV
04954-025
Figure 25. Power Shutdown Response Time, RF = 380 MHz
137
136
135
134
SUPPLY CURRENT (mA)
133
132
–40–25–1052035506580
Vp = 5
Vp = 4.75
TEMPERATURE (°C)
Figure 23. Supply Current vs. Temperature
04954-023
Rev. 0 | Page 10 of 24
Page 11
ADL5390
GENERAL STRUCTURE
THEORY OF OPERATION
The simplified block diagram given in Figure 26 shows a
matched pair of variable gain channels whose outputs are
summed and presented to the final output. The RF/IF signals
propagate from the left to the right, while the baseband gain
controls are placed above and below. The proprietary linearresponding variable attenuators offer excellent linearity, low
noise, and greater immunity from mismatches than other
commonly used methods.
Since the two independent RF/IF inputs can be combined in
arbitrary proportions, the overall function can be termed
“vector multiplication” as expressed by
= V
V
OUT
IRF
× (V
where:
V
V
IRF
IBB
and V
and V
are the RF/IF input vectors.
QRF
are the baseband input scalars.
QBB
VO is the built-in normalization factor, which is designed to be
0.285 V (1/3.5 V).
The overall voltage gain, in linear terms, of the I and Q channels
is proportional to its control voltage and scaled by the normalization factor, i.e., a full-scale gain of 1.75 (5 dB) for V
500 mV. A full-scale voltage gain of 1.75 defines a gain setpoint
of 1.0.
Due to its versatile functional form and wide signal dynamic
range, the ADL5390 can form the core of a variety of useful
functions such as quadrature modulators, gain and phase adjusters, and multiplexers. At maximum gain on one channel, the
output 1 dB compression point and noise floor referenced to
50 Ω are 11 dBm and −148 dBm/Hz, respectively. The broad
frequency response of the RF/IF and gain control ports allows
the ADL5390 to be used in a variety of applications at different
frequencies. The bandwidth for the RF/IF signal path extends
from approximately 20 MHz to beyond 2.4 GHz, while the gain
controls signals allow for modulation rates greater than 200 MHz.
IBB/VO
) + V
QRF
× (V
QBB/VO
)
of
I (Q)BB
,
V
IRF
I CHANNEL
SINGLE-ENDED
OR DIFFERENTIAL
V
,
QRF
Q CHANNEL
SINGLE-ENDED
OR DIFFERENTIAL
Figure 26. Simplified Architecture of the ADL5390
NOISE AND DISTORTION
The signal path for a particular channel of the ADL5390 consists basically of a preamplifier followed by a variable attenuator
and then an output driver. Each subblock contributes some level
of noise and distortion to the desired signal. As the channel gain
is varied, these relative contributions change. The overall effect
is a dependence of output noise floor and output distortion
levels on the gain setpoint.
For the ADL5390, the distortion is always determined by the
preamplifier. At the highest gain setpoint, the signal capacity, as
described by the 1 dB compression point (P1dB) and the thirdorder intercept (OIP3), are at the highest levels. As the gain is
reduced, the P1dB and OIP3 are reduced in exact proportion.
At the higher gain setpoints, the output noise is dominated by
the preamplifier as well. At lower gains, the contribution from
the preamplifier is correspondingly reduced and eventually a
noise floor, set by the output driver, is reached. As Figure 27
illustrates, the overall dynamic range defined as a ratio of OIP3
to output noise floor remains constant for the higher gain
setpoints. At some gain level, the noise floor levels off and the
dynamic range degrades commensurate with the gain reduction.
175
DYNAMIC RANGE = OIP3 – (OUTPUT NOISE
FLOOR (NO CARRIER))
170
BASEBAND INPUT
V-I
ATTENUATOR
V-I
ATTENUATOR
BASEBAND INPUT
I CHANNEL
V
IBB
LINEAR
LINEAR
V
QBB
Q CHANNEL
I-V
OUTPUT
DISABLE
SINGLE-ENDED
OR DIFFERENTIAL
50Ω OUTPUT
04954-026
Matching between the two gain channels is ensured by careful
layout and design. Since they are monolithic and arranged
symmetrically on the die, thermal and process gradients are
minimized. Typical gain and phase mismatch at maximum gain
are <0.5 dB and <0.5°.
Rev. 0 | Page 11 of 24
165
Hz)
×
160
155
150
DYNAMIC RANGE (dB
145
140
00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
GAIN SETPOINT
Figure 27. Dynamic Range Variation with Gain Setpoint
04954-027
Page 12
ADL5390
APPLICATIONS
USING THE ADL5390
The ADL5390 is designed to operate in a 50 Ω impedance system.
Figure 29 illustrates an example where the RF/IF inputs are
driven in a single-ended fashion, while the differential RF output is converted to a single-ended output with a RF balun. The
baseband gain controls for the I and Q channels are typically
driven from differential DAC outputs. The power supplies,
VPRF and VPS2, should be bypassed appropriately with 0.1 µF
and 100 pF capacitors. Low inductance grounding of the CMOP
and CMRF common pins is essential to prevent unintentional
peaking of the gain. The exposed paddle on the underside of the
package should be soldered to a low thermal and electrical
impedance ground plane.
RF INPUT AND MATCHING
The RF/IF inputs present 250 Ω resistive terminations to
ground. In general, the input signals should be ac-coupled
through dc-blocking capacitors. The inputs may be driven differentially or single-ended, in which case the unused inputs are
connected to common via the dc-blocking capacitors. The
ADL5390’s performance is not degraded by driving these inputs
single-ended. The input impedance can be reduced by placing
external shunt termination resistors to common on the source
side of the dc-blocking capacitors so that the quiescent dc-bias
RFIN_I
RFIN_Q
66.5Ω
R22
66.5Ω
C7
VP
R2
C2
10nF
C5
10nF
0.1µF
L1
0Ω
L2
0Ω
VP
C4
0.1µF
C1
10nF
C6
10nF
100pF
C8
100pF
C3
VPRF
CMRF
INPI
INMI
IPMQ
INPQ
CMRF
VPRF
C12
(SEE TEXT)
IFLP
IFLM
ADL5390
P
L
F
QFLM
Q
C11
(SEE TEXT)
QBBP QBBM
Figure 29. Basic Connections
IBBMIBBP
IBBP
QBBP
IBBM
level of the ADL5390 inputs is not affected, as shown in Figure
29. Capacitive reactance at the RF inputs can be compensated
for with series inductance. In fact, the customer evaluation
board has high impedance line traces between the shunt termination pads and the device input pins, which provides series inductance and improves the return loss at 1.9 GHz to better than
−15 dB with the shunt termination removed, as shown in Figure
The RF/IF outputs of the ADL5390, RFOP and RFOM, are open
collectors of a transimpedance amplifier that need to be pulled
up to the positive supply, preferably with RF chokes, as shown
in Figure 30. The nominal output impedance looking into each
individual output pin is 25 Ω. Consequently, the differential
output impedance is 50 Ω.
V
P
0.1µF
RFOP
120nH
10pF
10pF
50Ω
DIFFERENTIAL
1:1
RF
OUTPUT
04954-030
R
T
RFOM
I
G
SIG
Figure 30. RF Output Interface to the ADL5390 Showing
M
R
T
Coupling Capacitors, Pull-Up RF Chokes, and Balun
Since the output dc levels are at the positive supply, ac-coupling
capacitors are usually needed between the ADL5390 outputs
and the next stage in the system.
The RF output signal can be disabled by raising the DSOP pin
to the positive supply. The output disable function provides
>40 dB attenuation of the input signal, even at full gain. The
interface to DSOP is high impedance and the output disable
and output enable response times are <100 ns. If the output
disable function is not needed, the DSOP should be tied to
ground.
10
8
6
4
2
GAIN (dB)
0
–2
–4
RL = 50Ω
–10
10100100010000
Figure 31. Gain of the ADL5390 Using a Single-Ended Output with Different
Dummy Loads, R
on the Unused Output, Gain Setpoint = 1.0
L2
RL2 = OPEN
R
L2
R
L2
FREQUENCY (MHz)
= 50Ω
= SHORT
04954-043
A 1:1 RF broadband output balun, such as the ETC1-1-13 (M/ACOM), converts the differential output of the ADL5390 into a
single-ended signal. Note that the loss and balance of the balun
directly impact the apparent output power, noise floor, and gain/
phase errors of the ADL5390. In critical applications, narrow-band
baluns with low loss and superior balance are recommended.
If the output is taken in a single-ended fashion directly into a 50 Ω
load through a coupling capacitor, there will be an impedance
mismatch. This can be resolved with a 1:2 balun to convert the
single-ended 25 Ω output impedance to 50 Ω. If loss of signal
swing is not critical, a 25 Ω back termination in series with the
output pin can also be used. The unused output pin must still be
pulled up to the positive supply. The user may load it through a
coupling capacitor with a dummy load to preserve balance. The
mismatched gain of the ADL5390 when the output is singleended varies slightly with dummy load value, as shown in Figure
31.
DRIVING THE I-Q BASEBAND GAIN CONTROLS
The I and Q gain control inputs to the ADL5390 set the gain for
each channel. These inputs are differential and should normally
have a common-mode level of 0.5 V. However, when differentially driven, the common mode can vary from 250 mV to
750 mV while still allowing full gain control. Each input pair
has a nominal input swing of ±0.5 V differential around the
common-mode level. The maximum gain is achieved if the
differential voltage is equal to +500 mV or −500 mV. So with a
common-mode level of 500 mV, IBBP and IBBM will each
swing between 250 mV and 750 mV.
The I and Q gain control inputs can also be driven with a singleended signal. In this case, one side of each input should be tied
to a low noise 0.5 V voltage source (a 0.1 µF decoupling capacitor located close to the pin is recommended), while the other
input swings from 0 V to 1 V. Low speed, single-ended drive can
easily be achieved using 12-bit voltage output DACs such as
AD8303 (serial SPI® interface) or AD8582 (parallel interface)
DACs. A reference voltage should also be supplied. Differential
drive generally offers superior even-order distortion and lower
noise than single-ended drive.
The bandwidth of the baseband controls exceeds 200 MHz even
at full-scale baseband drive. This allows for very fast gain modulation of the RF input signal. In cases where lower modulation
bandwidths are acceptable or desired, external filter capacitors
can be connected across Pins IFLP to IFLM and Pins QFLP to
QFLM to reduce the ingress of baseband noise and spurious
signal into the control path.
Rev. 0 | Page 13 of 24
Page 14
ADL5390
The 3 dB bandwidth is set by choosing C
following equation:
nF10kHz45
external
×
pF0.5
+
≈
f
dB3
C
This equation has been verified for values of C
0.1 µF (bandwidth settings of approximately 4.5 kHz to 43 MHz).
INTERFACING TO HIGH SPEED DACs
The AD977x family of dual DACs is well suited to driving the I
and Q gain controls of the ADL5390 with fast modulating signals. While these inputs can in general be driven by any DAC,
the differential outputs and bias level of the ADI TxDAC® family allows for a direct connection between DAC and modulator.
The AD977x family of dual DACs has differential current outputs. The full-scale current is user programmable and is usually
set to 20 mA, that is each output swings from 0 mA to 20 mA.
The basic interface between the AD9777 DAC outputs and the
ADL5390 I and Q gain control inputs is shown in Figure 32.
Resistors R1 and R2 (R1 = R2) set the dc bias level according to
the following equation:
Bias Level = Average Output Current × R1
For example, if the full-scale current from each output is 20 mA,
each output will have an average current of 10 mA. Therefore,
to set the bias level to the recommended 0.5 V, R1 and R2
should be set to 50 Ω each. R1 and R2 should always be equal.
If R3 is omitted, this will result in an available swing from the
DAC of 2 V p-p differential, which is twice the maximum voltage
range required by the ADL5390. DAC resolution can be maximized by adding R3, which scales down this voltage according
to the following equation:
Figure 33 shows the relationship between the value of R3 and
the peak baseband voltage with R1 and R2 equal to 50 Ω. As
shown in Figure 33, a value of 100 Ω for R3 will provide a
peak-peak swing of 1 V p-p differential into the ADL5390’s
I and Q inputs.
04954-032
MAX
R2
+
⎤
⎥
R3R2
⎥
⎦
()()
⎡
1||2
R3R2R1I
−×+×
⎢
⎢
⎣
When using a DAC, low-pass image reject filters are typically
used to eliminate the Nyquist images produced by the DAC.
They also provide the added benefit of eliminating broadband
noise that might feed into the modulator from the DAC.
Rev. 0 | Page 14 of 24
Page 15
ADL5390
(
[
(
)
=
GENERALIZED MODULATOR
The ADL5390 can be configured as a traditional IQ quadrature
modulator or as a linear vector modulator by applying signals
that are in quadrature to the RF/IF input channels. Since the
quadrature generation is performed externally, its accuracy and
bandwidth are determined by the user. The user-defined bandwidth is attractive for multioctave or lower IF applications
where on-chip, high accuracy quadrature generation is traditionally difficult or impractical. The gain control pins (I
and Q
) become the in-phase (I) and quadrature (Q) base-
BBP/M
BBP/M
band inputs for the quadrature modulator and the gain/phase
control for the vector modulator. The wide modulation bandwidths of the gain control interface allow for high fidelity baseband signals to be generated for the quadrature modulator and
for high speed gain and phase adjustments to be generated for
the vector modulator.
RF/IF signals can be introduce to the ADL5390 in quadrature
by using a two-way 90
o
power splitter such as the Mini-Circuits
QCN-12. Each output of an ideal 90o power splitter is 3 dB
smaller than the input and has a 90o phase difference from the
other output. In reality, the 90
o
power splitter will have its own
insertion loss, which can be different for each output, causing a
magnitude imbalance. Furthermore, quadrature output will not
be maintained over a large frequency range, introducing a phase
imbalance. The type of 90
o
power splitter that should be used
for a particular application will be determined by the frequency,
bandwidth, and accuracy needed. In some applications minor
magnitude and phase imbalances can be adjusted for in the
I/Q gain control inputs.
VECTOR MODULATOR
V
q
MAX GAIN = 5dB
+0.5
|A|
A
θ
V
i
+0.5–0.5
inputs V
IBB
and V
the vector gain, which can also be expressed as a magnitude and
phase. By applying different combinations of baseband inputs,
any vector gain within the unit circle can be programmed. The
magnitude and phase (with respect to 90
power splitter will directly affect this representation and could
be seen as an offset and skew of the circle.
A change in sign of V
sign of the gain or as a 180° phase change. The outermost circle
represents the maximum gain magnitude. The circle origin
implies, in theory, a gain of 0. In practice, circuit mismatches
and unavoidable signal feedthrough limit the minimum gain to
approximately −30 dB. The phase angle between the resultant
gain vector and the positive x-axis is defined as the phase shift.
Note that there is a nominal, systematic insertion phase through
the ADL5390 to which the phase shift is added. In the following
discussions, the systematic insertion phase is normalized to 0°.
The correspondence between the desired gain and phase and
the Cartesian inputs V
metric identities
where:
V
is the baseband scaling constant (285 mV).
O
V
and V
IBB
QBB
centered around 500 mV, respectively (V
V
= V
QBB
QBBP
Note that when evaluating the arctangent function, the proper
phase quadrant must be selected. For example, if the principal
value of the arctangent (known as arctangent(x)) is used, quadrants 2 and 3 would be interpreted mistakenly as quadrants 4
and 1, respectively. In general, both V
concert to modulate the gain and the phase.
. The resultant of their vector sum represents
QBB
o
) accuracy of the 90o
or V
IBB
IBB
IBB
QBB
can be viewed as a change in
QBB
and V
)
is given by simple trigono-
QBB
22
//
VVVVGain+=
OQBBO
]
()
VVarctanPhase/
IBB
are the differential I and Q baseband voltages
= V
− V
IBBP
IBBM
are needed in
QBB
− V
QBBM
).
and V
IBB
IBB
;
Pure amplitude modulation is represented by radial movement
of the gain vector tip at a fixed angle, while pure phase modula-
MIN GAIN < –30dB
–0.5
Figure 34. Vector Gain Representation
04954-034
The ADL5390 can be used as a vector modulator by driving the
RF I and Q inputs single-ended through a 90
o
power splitter. By
controlling the relative amounts of I and Q components that are
summed, continuous magnitude and phase control of the gain
is possible. Consider the vector gain representation of the
ADL5390 expressed in polar form in Figure 34. The attenuation
factors for the RF I and Q signal components are represented on
the x-axis and y-axis, respectively, by the baseband gain control
tion is represented by rotation of the tip around the circle at a
fixed radius. Unlike traditional I-Q modulators, the ADL5390 is
designed to have a linear RF signal path from input to output.
Traditional I-Q modulators provide a limited LO carrier path
through which any amplitude information is removed.
VECTOR MODULATOR EXAMPLE—CDMA2000
The ADL5390 can be used as a vector modulator by driving the
RF I and Q inputs (INPI and INPQ) single-ended through a 90
power splitter and controlling the magnitude and phase using
the gain control inputs. To demonstrate operation as a vector
modulator, an 880 MHz single-carrier CDMA2000 test model
o
signal (forward pilot, sync, paging, and six traffic as per
Rev. 0 | Page 15 of 24
Page 16
ADL5390
–
3GPP2 C.S0010-B, Table 6.5.2.1) was applied to the ADL5390.
A cavity-tuned filter was used to reduce noise from the signal
source being applied to the device. The 4.6 MHz pass band of
this filter is apparent in the subsequent spectral plots.
Figure 35 shows the output signal spectrum for a programmed
gain and phase of 5 dB and 45
V
= V
IBB
V
IBBM
= 0.353 V (centered around 500 mV), i.e., V
QBB
= V
QBBP
− V
= 0.353 V. Adjacent channel power is
QBBM
measured in 30 kHz resolution bandwidth at 750 kHz and
1.98 MHz carrier offset. Noise floor is measured at ±4 MHz
carrier offset in a 1 MHz resolution bandwidth.
REF LVL
5dBm
0.7dB OFFSET
0
–10
–20
–30
1AVG
–40
–50
–60
–70
Cl2
–80
–90
100
CENTER 880MHz500kHz/SPAN 5MHz
Figure 35. Output Spectrum, Single-Carrier CDMA2000 Test Model at −5 dBm,
= VQ = 0.353 V, ACP Measured at 750 kHz and 1.98 MHz Carrier Offset,
V
I
Input Signal–Filtered Using a Cavity-Tuned Filter (Pass Band = 4.6 MHz)
Cl2
MARKER 1 [T1]
–14.38dBm
880.00755511MHz
Holding the I and Q gain control voltages steady at 0.353 V,
input power was swept. Figure 36 shows the resulting output
power, noise floor, and adjacent channel power ratio. The noise
floor is presented as noise in a 1 MHz bandwidth as defined by
the 3GPP2 specification.
ACP is still in compliance with the standard (<−45 dBc @
750 kHz and <−60 dBc @ 1.98 MHz) even with output powers
greater than +3 dBm. At low output power levels, ACP at
1.98 MHz carrier offset degrades as the noise floor of the
ADL5390 becomes the dominant contributor to measured ACP.
Measured noise at 4 MHz carrier offset begins to increase
sharply above 2 dBm output power. This increase is not due to
noise, but results from increased carrier-induced distortion. As
output power drops below 2 dBm, the noise floor drops towards
−90 dBm.
With a fixed input power of 2.16 dBm, the output power was
again swept by changing V
and V
IBB
from 0 V to 500 mV.
QBB
The resulting output power, ACP, and noise floor are shown in
Figure 37.
5
–2
–9
–16
–23
–30
RF OUTPUT POWER (dBm)
–37
–44
00.10.20.30.40.5
ACP: 1.98MHz OFFSET, 30kHz RBW
NOISE: 4MHz OFFSET, 1MHz RBW
V
vs. V
OUT
IBB/VQBB
ACP: 750kHz OFFSET, 30kHz RBW
V
I(Q)BB
Figure 37. Output Power, Noise, and ACP vs. I and Q Control Voltages,
CDMA2000 Test Model, V
= VQ, ACP Measured in 30 kHz RBW at ±750 MHz
I
and ±1.98 MHz Carrier Offset, Noise Measured at ±4 MHz Carrier Offset
–30
–40
–50
–60
–70
–80
–90
–100
ACP (dBc)
NOISE (dBm @ 4MHz Carrier Offset)
04954-045
In contrast to Figure 36, Figure 37 shows that for a fixed input
power, ACP remains fairly constant as gain and phase are
changed (this is not true for very high RF input powers) until
the noise floor of the ADL5390 becomes the dominant contributor to the measured ACP.
–50
–60
–70
ACP (dBc)
–80
–90
–100
–30–25–20–15–10–505
ACP: 1.98MHz OFFSET, 30kHz RBW
NOISE: 4MHz OFFSET, 1MHz RBW
ACP: 750kHz OFFSET, 30kHz RBW
OUTPUT POWER (dBm)
–50
–60
–70
–80
–90
–100
NOISE (dBm @ 4MHz Carrier Offset)
04954-044
Figure 36. Noise and ACP vs. Output Power, Single-Carrier CDMA2000 Test
Model, VI = VQ = 0.353, ACP Measured in 30 kHz RBW at ±750 kHz and
The ADL5390 can be used as a quadrature modulator by driving
the RF I and Q inputs (INPI and INPQ) single-ended through a
o
90
phase splitter to serve as the LO input. I/Q modulation is
applied to the baseband I and Q gain control inputs (IBBP/IBBM
and QBBP/QBBM). A simplified schematic is shown in Figure
38.
I DATA
LO IN
50Ω
SUM
PORT
QCN-12
TERM
PORT
90° PHASE
SPLITTER
PORT 1
PORT 2
10nF
66.5Ω
10nF
66.5Ω
INPI
INPQ
Figure 38. Quadrature Modulator Application
Single sideband performance of a quadrature modulator is
determined by the magnitude and phase balance (compared to
o
a 90
offset) at the summation point of the I and Q signals.
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
o
phase splitter. However, phase and magnitude
differences in the 90o phase splitter can be corrected by adjusting
the magnitude and phase of the I and Q data. Figure 39 shows
the performance of the ADL5390 used in conjunction with MiniCircuits QCN-12 90
o
power splitter. Figure 40 shows the single
sideband improvement as the I and Q data is adjusted in magnitude
and phase to achieve better single sideband performance.
IBBP
IBBM
RFOM
ADL5390
Q DATA
RFOP
QBBP
QBBM
o
phase splitter. Good
10nF
10nF
(M/A-COM)
15
34
ETC1-1-13
ROFP
*
RBW 3kHz
VWB 10kHz
SWT 780ms
A
1
4
04954-039
1 AP
CLRWR
REF 7dBmATT 35dB
DESIRED SIDEBAND
–16.20dBm
0
900.998397436MHz
UNDESIRED SIDEBAND
–10
–23.27dB
–1.996794872MHz
–20
THIRD BASEBAND HARMONIC
–37.38dB
–30
–4.004807692MHz
LO FEEDTHROUGH
–40
–41.27dB
–998.397435897kHz
–50
3
–60
–70
-80
-
CENTER 900MHz700kHz/SPAN 7MHz
2
Figure 39. SSB Quadrature Modulator Result Us ing External 90° Phase Splitter,
= −15 dBm, VIBB = VQBB = 0.5 V
RF P
IN
(With Reference to a Common-Mode Voltage of 0.5 V )
*
RBW 3kHz
REF 7dBmATT 35dB
DESIRED SIDEBAND
0
04954-038
1 AP
CLRWR
–16.78dBm
900.998397436MHz
UNDESIRED SIDEBAND
–10
–51.81dB
–1.996794872MHz
–20
THIRD BASEBAND HARMONIC
–38.45dB
–30
–4.004807692MHz
LO FEEDTHROUGH
–40
–41.49dB
–998.397435897kHz
–50
–60
–70
–80
–90
CENTER 900MHz700kHz/SPAN 7MHz
VWB 10kHz
SWT 780ms
A
04954-046
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
Voltage of 0.5 V), I/Q Phase O ffset by 3
o
, and Magnitude Offset by 0.5 V
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 demonstrates 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
o
phase splitters—AD8340,
AD8341, AD8345, AD8346, AD8349—that cover a variety of
frequency bands.
Rev. 0 | Page 17 of 24
Page 18
ADL5390
RBW 10kHz
*
VBW 300kHz
REF –26.6dBm
1 RM
AVG
*
–100
–110
–120
–30
–40
–50
–60
–70
–80
–90
POS –26.623dBm
CENTER 880MHz1.29MHz/SPAN 12.9MHz
STANDARD: CDMA IS95C CLASS 0 FWD
Tx CHANNELS
CH1 (REF)
CH2
CH3
TOTAL
ATT 5dB
*
–22.93dBm
–22.83dBm
–22.95dBm
–18.13dBm
*
SWT 4s
*
ADJACENT CHANNEL
LOWER –59.25dB
UPPER –59.43dB
ALTERNATE CHANNEL
LOWER –62.79dB
UPPER –63.11dB
2ND ALTERNATE CHANNEL
LOWER –60.71dB
UPPER –60.32dB
A
NOR
Figure 41. ADL5390 as a Quadrature Modulator with the Use of an External
90° Phase Splitter, RF/LO Power = −1 dBm and Gain Control Inputs Driven
Differentially with 0.353 V
–69
–70
–71
–72
–73
–74
–75
NOISE (dBC) (1MHz RBW)
–76
–77
–78
–25–20–15–10–50
NOISE (dBc) - 8MHz OFFSET - 1MHz RBW
, 3-Carrier CDMA2000 I/Q Data
P-P
OUTPUT POWER (dBm)
04954-031
Figure 42. Noise vs. Output Power
04954-037
RF MULTIPLEXER
The ADL5390 may also be used as an RF multiplexer. In this
application, two RF signals are applied to the INPI and INPQ
inputs, and the baseband voltages control which of the two RF
signals appears at the output. Figure 43 illustrates this application and shows that with V
ence to a common-mode voltage of 0.5 V). The INPI signal is
presented to the output. Then, when V
0.0 and V
Lastly, as V
the output. With V
remains equal to zero, there is no RF output.
QBB
transitions to 0.5 V, the INPQ signal appears at
QBB
= 0.0 and V
IBB
output is typically >40 dB at 380 MHz.
TEK STOPPED 200 Acqs24 AUG 04 11:08:40
CH2
2
CH3
CH1
3
1
CH1 200mV Ω CH2 500mV Ω D
CH3 500mV Ω D
S
Figure 43. ADL5390 in RF Multiplexer Application
= 0.5 and V
IBB
= 0.0, the isolation to the
QBB
V
IBB
V
QBB
RF OUTPUT
M 40.0ns 1.25GS/s 800ps/pt
S
A CH2 780mV
= 0.0 (with refer-
QBB
transitions to V
IBB
IBB
04954-047
=
Rev. 0 | Page 18 of 24
Page 19
ADL5390
EVALUATION BOARD
The evaluation board circuit schematic for the ADL5390 is
shown in Figure 44.
The evaluation board is configured to be driven from a
single-ended 50 Ω source. Although the input of the ADL5390
is differential, it may be driven single-ended with no loss of
performance.
The low-pass corner frequency of the baseband I and Q channels can be reduced by installing capacitors in the C11 and C12
positions. The low-pass corner frequency for either channel is
approximated by
nF10kHz45
external
×
pF0.5
+
f
≈
dB3
C
On this evaluation board, the I and Q baseband circuits are
identical to each other, so the following description applies to
each. The connections and circuit configuration for the I/Q
baseband inputs are described in Table 4.
The baseband input of the ADL5390 requires a differential voltage drive. The evaluation board is set up to allow such a drive
by connecting the differential voltage source to QBBP and
QBBM. The common-mode voltage should be maintained at
approximately 0.5 V. For this configuration, Jumpers W1 to W4
should be removed.
The baseband input of the evaluation board may also be driven
with a single-ended voltage. In this case, a bias level is provided
to the unused input from Potentiometer R10 by installing either
W1 or W2.
Setting SW1 in Position B disables the ADL5390 output amplifier.
With SW1 set to Position A, the output amplifier is enabled. With
SW1 set to Position A, an external voltage signal, such as a pulse,
can be applied to the DSOP SMA connector to exercise the
output amplifier enable/disable function.
I Channel Baseband Interface. Resistors R7 and R9 may be installed to
accommodate a baseband source that requires a specific terminating
impedance. Capacitors C15 and C19 are bypass capacitors. For single-ended
baseband drive, the Potentiometer R11 can be used to provide a bias level to
the unused input (install either W3 or W4).
Q Channel Baseband Interface. See the I Channel Baseband Interface section.
Baseband Low-Pass Filtering. By adding capacitor C11 between QFLP and
QFLM, and capacitor C12 between IFLP and IFLM, the 3 dB low-pass corner
frequency of the baseband interface can be reduced from 230 MHz (nominal)
as given by the equation in the Evaluation Board section.
Output Interface. The 1:1 balun transformer, T1, converts the 50 Ω differential
output to 50 Ω single-ended. C17 and C18 are dc blocks. L3 and L4 provide dc
bias for the output.
I and Q Channel RF Input Interface. The single-ended impedance to the
ADL5390 RF inputs is 200 Ω. Shunt terminations R2 and R22 of 66.5 Ω bring the
impedances to 50 Ω. C2 and C5 are dc blocks. C1 and C6 are used to ac-couple
the unused side of the differential inputs to common.
Power Supply Decoupling.
Output Disable Interface. The output stage of the ADL5390 is disabled by
applying a high voltage to the DSOP pin by moving SW1 to Position B. The
output stage is enabled moving SW1 to Position A. The output disable
function can also be exercised by applying an external high or low voltage to
the DSOP SMA connector with SW1 in Position A.