FEATURES
Measures Gain/Loss and Phase up to 2.7 GHz
Dual Demodulating Log Amps and Phase Detector
Input Range –60 dBm to 0 dBm in a 50 ⍀ System
Accurate Gain Measurement Scaling (30 mV/dB)
Typical Nonlinearity < 0.5 dB
Accurate Phase Measurement Scaling (10 mV/Degree)
Typical Nonlinearity < 1 Degree
Measurement/Controller/Level Comparator Modes
Operates from Supply Voltages of 2.7 V–5.5 V
Stable 1.8 V Reference Voltage Output
Small Signal Envelope Bandwidth from DC to 30 MHz
APPLICATIONS
RF/IF PA Linearization
Precise RF Power Control
Remote System Monitoring and Diagnostics
Return Loss/VSWR Measurements
Log Ratio Function for AC Signals
RF/IF Gain and Phase Detector
AD8302
FUNCTIONAL BLOCK DIAGRAM
PRODUCT DESCRIPTION
The AD8302 is an innovative, fully integrated system for measuring gain/loss and phase in numerous receive, transmit, and
instrumentation applications. It requires few external components and a single supply of 2.7 V–5.5 V. The ac-coupled input
signals can range from –60 dBm to 0 dBm in a 50 Ω system, from
low frequencies up to 2.7 GHz. The outputs provide an accurate measurement of either gain or loss over a ±30 dB range
scaled to 30 mV/dB, and of phase over a 0°–180° range scaled to
10 mV/degree. Both subsystems have an output bandwidth of
30 MHz, which may optionally be reduced by the addition of
external filter capacitors. The AD8302 can be used in direct
control mode to servo gain and phase of a signal chain toward
predetermined setpoints.
The AD8302 comprises a closely matched pair of demodulating
logarithmic amplifiers, each having a 60 dB measurement range.
By taking the difference of their outputs, a measurement of
the magnitude ratio or gain between the two input signals is
available. These signals may even be at different frequencies,
allowing the measurement of conversion gain or loss. The AD8302
may be used to determine absolute signal level by applying the
unknown signal to one input and a calibrated ac reference signal
to the other. With the output stage feedback connection disabled, a comparator may be realized, using the setpoint pins
MSET and PSET to program the thresholds.
The signal inputs are single-ended, allowing them to be matched
and connected directly to a directional coupler. Their input
impedance is nominally 3 kΩ at low frequencies.
The AD8302 includes a phase detector of the multiplier type,
but with precise phase balance, driven by the fully limited signals appearing at the outputs of the two logarithmic amplifiers.
Thus, the phase accuracy measurement is independent of signal
level over a wide range.
The phase and gain output voltages are simultaneously available
at loadable ground referenced outputs over the standard output
range of 0 V to 1.8 V. The output drivers can source or sink up
to 8 mA. A loadable, stable reference voltage of 1.8 V is available for precise repositioning of the output range by the user.
In controller applications, the connection between the gain
output pin VMAG and the setpoint control pin MSET is broken.
The desired setpoint is presented to MSET and the VMAG
control signal drives an appropriate external variable gain device.
Likewise, the feedback path between the phase output pin VPHS
and its setpoint control pin PSET may be broken, to allow
operation as a phase controller.
The AD8302 is fabricated on Analog Devices’ proprietary, highperformance 25 GHz SOI complementary bipolar IC process. It is
available in a 14-lead TSSOP package and operates over a –40°C
to +85°C temperature range. An evaluation board is 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. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices.
resistors connected to INPA and INPB, for Phase measurement P
(TA = 25ⴗC, VS = 5 V, VMAG shorted to MSET, VPHS shorted to PSET, 52.3 ⍀ shunt
= P
INPA
unless otherwise noted)
INPB
ParameterConditionsMinTypMaxUnit
OVERALL FUNCTION
Input Frequency Range>02700MHz
Gain Measurement RangeP
Phase Measurement Rangeφ
at INPA, PIN at INPB = –30 dBm± 30dB
IN
at INPA > φIN at INPB± 90Degree
IN
Reference Voltage OutputPin VREF, –40°C ≤ TA ≤ +85°C1.721.81.88V
INPUT INTERFACEPins INPA and INPB
Input Simplified Equivalent CircuitTo AC Ground, f ≤ 500 MHz3储2kΩ储pF
Input Voltage RangeAC-Coupled (0 dBV = 1 V rms)–73–13dBV
re: 50 Ω–600dBm
Center of Input Dynamic Range–43dBV
–30dBm
MAGNITUDE OUTPUTPin VMAG
Output Voltage Minimum20 × Log (V
Output Voltage Maximum20 × Log (V
Center Point of Output (MCP)V
INPA
= V
INPB
INPA/VINPB
INPA/VINPB
) = –30 dB30mV
) = +30 dB1.8V
900mV
Output CurrentSource/Sink8mA
Small Signal Envelope BandwidthPin MFLT Open30MHz
Slew Rate40 dB Change, Load 20 pF储10 kΩ25V/µs
Response Time
Rise TimeAny 20 dB Change, 10%–90%50ns
Fall TimeAny 20 dB Change, 90%–10%60ns
Settling TimeFull-Scale 60 dB Change, to 1% Settling300ns
PHASE OUTPUTPin VPHS
Output Voltage MinimumPhase Difference 180 Degrees30mV
Output Voltage MaximumPhase Difference 0 Degrees1.8V
= φ
Phase Center PointWhen φ
INPA
± 90°900mV
INPB
Output Current DriveSource/Sink8mA
Slew Rate25V/µs
Small Signal Envelope Bandwidth30MHz
Response TimeAny 15 Degree Change, 10%–90%40ns
120 Degree Change C
= 1 pF, to 1% Settling500ns
FILT
100 MHzMAGNITUDE OUTPUT
Dynamic Range± 1 dB Linearity P
± 0.5 dB Linearity P
± 0.2 dB Linearity P
= –30 dBm (V
REF
= –30 dBm (V
REF
= –30 dBm (V
REF
= –43 dBV)58dB
REF
= –43 dBV)55dB
REF
= –43 dBV)42dB
REF
SlopeFrom Linear Regression29mV/dB
Deviation vs. TemperatureDeviation from Output at 25°C
–40°C ≤ T
≤ +85°C, P
A
INPA
= P
= –30 dBm0.25dB
INPB
Deviation from Best Fit Curve at 25°C
Gain Measurement BalanceP
–40°C ≤ T
= P
INPA
≤ +85°C, P
A
= –5 dBm to –50 dBm0.2dB
INPB
= ± 25 dB, P
INPA
= –30 dBm0.25dB
INPB
PHASE OUTPUT
Dynamic RangeLess than ± 1 Degree Deviation from Best Fit Line145Degree
Less than 10% Deviation in Instantaneous Slope143Degree
Slope (Absolute Value)From Linear Regression about –90° or +90°10mV/Degree
Deviation vs. TemperatureDeviation from Output at 25°C
SlopeFrom Linear Regression28.7mV/dB
Deviation vs. TemperatureDeviation from Output at 25°C
–40°C ≤ T
≤ +85°C, P
A
Deviation from Best Fit Curve at 25°C
Gain Measurement BalanceP
–40°C ≤ T
INPA
= P
≤ +85°C, P
A
INPB
PHASE OUTPUT
Dynamic RangeLess than ± 1 Degree Deviation from Best Fit Line143Degree
Less than 10% Deviation in Instantaneous Slope143Degree
Slope (Absolute Value)From Linear Regression about –90° or +90°10.1mV/Degree
DeviationLinear Deviation from Best Fit Curve at 25°C
SlopeFrom Linear Regression27.5mV/dB
Deviation vs. TemperatureDeviation from Output at 25°C
–40°C ≤ T
≤ +85°C, P
A
Deviation from Best Fit Curve at 25°C
Gain Measurement BalanceP
–40°C ≤ T
INPA
= P
≤ +85°C, P
A
INPB
PHASE OUTPUT
Dynamic RangeLess than ± 1 Degree Deviation from Best Fit Line128Degree
Less than 10% Deviation in Instantaneous Slope120Degree
Slope (Absolute Value)From Linear Regression about –90° or +90°10.2mV/Degree
DeviationLinear Deviation from Best Fit Curve at 25°C
SlopeFrom Linear Regression27.5mV/dB
Deviation vs. TemperatureDeviation from Output at 25°C
–40°C ≤ T
≤ +85°C, P
A
Deviation from Best Fit Curve at 25°C
Gain Measurement BalanceP
–40°C ≤ T
INPA
= P
≤ +85°C, P
A
INPB
PHASE OUTPUT
Dynamic RangeLess than ± 1 Degree Deviation from Best Fit Line115Degree
Less than 10% Deviation in Instantaneous Slope110Degree
Slope (Absolute Value)From Linear Regression about –90° or +90°10mV/Degree
DeviationLinear Deviation from Best Fit Curve at 25°C
Maximum Junction Temperature . . . . . . . . . . . . . . . . 125°C
Operating Temperature Range . . . . . . . . . . . –40°C to +85°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Lead Temperature Range (Soldering 60 sec) . . . . . . . . 300°C
NOTES
1
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.
2
JEDEC 1S Standard (2-layer) board data.
PIN FUNCTION DESCRIPTIONS
Equivalent
Pin No.MnemonicFunctionCircuit
1, 7COMMDevice Common. Connect to low impedance ground.
2INPAHigh Input Impedance to Channel A. Must be ac-coupled.Circuit A
3OFSAA capacitor to ground at this pin sets the offset compensation filter cornerCircuit A
and provides input decoupling.
4VPOSVoltage Supply (V
), 2.7 V to 5.5 V.
S
5OFSBA capacitor to ground at this pin sets the offset compensation filter cornerCircuit A
and provides input decoupling.
6INPBInput to Channel B. Same structure as INPA.Circuit A
8PFLTLow-Pass Filter Terminal for the Phase Output.Circuit E
9VPHSSingle-Ended Output Proportional to the Phase Difference between INPACircuit B
and INPB.
10PSETFeedback Pin for Scaling of VPHS Output Voltage in Measurement Mode.Circuit D
Apply a setpoint voltage for controller mode.
11VREFInternally-Generated Reference Voltage (1.8 V Nominal).Circuit C
12MSETFeedback Pin for Scaling of VMAG Output Voltage Measurement Mode.Circuit D
Accepts a set point voltage in controller mode.
13VMAGSingle-Ended Output. Output voltage proportional to the decibel ratio
of signals applied to INPA and INPB.Circuit B
14MFLTLow-Pass Filter Terminal for the Magnitude Output.Circuit E
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
the AD8302 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.
ORDERING GUIDE
Package
Model Temperature RangePackage DescriptionOption
AD8302ARU–40°C to +85°CTube, 14-Lead TSSOPRU-14
AD8302ARU-REEL13" Tape and Reel
AD8302ARU-REEL77" Tape and Reel
AD8302-EVALEvaluation Board
–4–
REV. 0
AD8302
INPA(INPB)
OFSA(OFSB)
VPOS
COMM
10k⍀
5k⍀
Circuit C
100mV
4k⍀
4k⍀
10pF
COMM
Circuit A
VREF
VPOS
+
ON TO
LOG-AMP
–
MSET
(PSET)
VPOS
10k⍀
10k⍀
COMM
Circuit D
ACTIVE LOADS
750⍀
2k⍀
VPOS
CLASS A-B
CONTROL
COMM
Circuit B
25⍀
VPOS
COMM
Circuit E
VMAG
(VPHS)
MFLT
(PFLT)
1.5pF
Figure 1. Equivalent Circuits
REV. 0
–5–
AD8302
Typical Performance Characteristics
(VS = 5 V, V
is the reference input and V
INPB
is swept unless otherwise
INPA
noted. All references to dBm are referred to 50 ⍀. For the Phase Output curves the input signal levels are equal unless otherwise noted.)
VMAG – dB
VMAG – dB
1.80
1.65
1.50
1.35
1.20
1.05
0.90
0.75
0.60
0.45
0.30
0.15
1.80
1.65
1.50
1.35
1.20
1.02
0.90
0.75
0.60
0.45
0.30
0.15
0
–30
0
–30
–20–100102030
–20–100102030
MAGNITUDE RATIO – dB
°
C, +25°C, and +85°C,
MAGNITUDE RATIO – dB
°
C, +25°C, and +85°C,
3.0
2.5
2.0
1.5
1.0
0.5
0.0
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
3.0
2.5
2.0
1.5
1.0
0.5
0.0
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
2.0
1.8
1.6
1.4
1.2
1.0
VMAG – V
0.8
0.6
0.4
0.2
0
–25 –20 –15 –10 –5 0 5 1015202530
–30
MAGNITUDE RATIO – dB
100
2700
900
2200
1900
TPC 1. Magnitude Output (VMAG) vs. Input Level Ratio
(Gain) V
TPC 4. VMAG and Log Conformance vs. Input Level Ratio
(Gain), Frequency 900 MHz, –40
Reference Level = –30 dBm
TPC 5. VMAG and Log Conformance vs. Input Level Ratio
(Gain), Frequency 1900 MHz, –40
Reference Level = –30 dBm
ERROR IN VMAG – dB
ERROR IN VMAG – dB
1.80
1.65
1.50
1.35
1.20
1.05
0.90
VMAG – V
0.75
0.60
0.45
0.30
0.15
0
–30
–20–100 102030
MAGNITUDE RATIO – dB
TPC 3. VMAG Output and Log Conformance vs. Input
Level Ratio (Gain), Frequency 100 MHz, –40
°
and +85
C, Reference Level = –30 dBm
°
C, +25°C,
3.0
2.5
2.0
1.5
1.0
0.5
0.0
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
1.80
1.65
1.50
1.35
1.20
1.02
0.90
0.75
VMAG – dB
ERROR IN VMAG – dB
0.60
0.45
0.30
0.15
0
–30
–20–100102030
MAGNITUDE RATIO – dB
TPC 6. VMAG Output and Log Conformance vs. Input
Level Ratio (Gain), Frequency 2200 MHz, –40
°
and +85
C, Reference Level = –30 dBm
–6–
°
C, +25°C,
3.0
2.5
2.0
1.5
1.0
0.5
0.0
–0.5
–1.0
ERROR IN VMAG – dB
–1.5
–2.0
–2.5
–3.0
REV. 0
AD8302
3.0
2.5
2.0
1.5
1.0
0.5
0.0
–0.5
–1.0
ERROR IN VMAG – dB
–1.5
–2.0
–2.5
–3.0
–25 –20 –15 –10 –5 0 5 1015202530
–30
+85 C
+85 C
–40 C
MAGNITUDE RATIO – dB
–40 C
+25 C
TPC 7. Distribution of Magnitude Error vs. Input Level
Ratio (Gain), Three Sigma to Either Side of Mean, Fre-
°
quency 900 MHz, Temperatures –40
C, +25°C, and +85°C,
Reference Level = –30 dBm
3.0
2.5
2.0
1.5
1.0
0.5
0.0
–0.5
–1.0
ERROR IN VMAG – dB
+25 C
–1.5
–2.0
–2.5
–3.0
–25 –20 –15 –10 –5 0 5 1015202530
–30
–40 C
MAGNITUDE RATIO – dB
–40 C
+85 C
+85 C
2.0
1.8
1.6
1.4
1.2
1.0
VMAG – V
0.8
0.6
0.4
0.2
0.0
–30
–25 –20 –15 –10 –5 0 5 1015202530
MAGNITUDE RATIO – dB
TPC 10. Distribution of VMAG vs. Input Level Ratio (Gain),
Three Sigma to Either Side of Mean, Frequency 1900 MHz,
°
Temperatures Between –40
C, and +85°C, Reference Level
= –30 dBm
–30dBm
3.0
2.5
2.0
1.5
1.0
0.5
0.0
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
ERROR IN VMAG – dB
1.8
1.6
1.4
1.2
1.0
0.8
VMAG – V
–30dBm
0.6
0.4
0.2
0.0
–30
–45dBm
–15dBm
–20–100 102030
MAGNITUDE RATIO – dB
–40dBm
–15dBm
TPC 8. Distribution of Error vs. Input Level Ratio (Gain),
Three Sigma to Either Side of Mean, Frequency 1900 MHz,
°
C, +25°C, and +85°C, Reference Level = –30 dBm
–40
3.0
2.5
2.0
1.5
1.0
0.5
0.0
–0.5
–1.0
ERROR IN VMAG – dB
–1.5
–2.0
–2.5
–3.0
–30
+25 C
–25 –20 –15 –10 –5 0 5 1015202530
–40 C
+85 C
+85 C
–40 C
MAGNITUDE RATIO – dB
TPC 9. Distribution of Magnitude Error vs. Input Level
Ratio (Gain), Three Sigma to Either Side of Mean, Frequency 2200 MHz, Temperatures –40°C, +25°C, and +85°C,
Reference Level = –30 dBm
REV. 0
TPC 11. VMAG Output and Log Conformance vs. Input
Level Ratio (Gain), Reference Level = –10 dBm, –30 dBm,
and –45 dBm, Frequency 1900 MHz
1.10
P
= P
1.05
1.00
0.95
0.90
VMAG – V
0.85
0.80
0.75
–65
–60 –55 –50 –45 –40 –35 –30
INPA
P
INPA
P
INPA
INPUT LEVEL – dBm
TPC 12. VMAG Output vs. Input Level for P
P
INPA
= P
+5 dB, P
INPB
INPA
= P
+ 5dB
INPB
= P
INPB
= P
– 5dB
INPB
–25 –20 –15 –10 –50
–5 dB, Frequency 1900 MHz
INPB
INPA
= P
–7–
INPB
,
AD8302
1.06
1.04
1.02
1.00
0.98
0.96
0.94
0.92
0.90
0.88
VMAG – V
0.86
0.84
0.82
0.80
0.78
0.76
0.74
200 400 600 800 1000 1200 1400
TPC 13. VMAG Output vs. Frequency, for P
P
INPA
= P
CHANGE IN SLOPE – mV
+5 dB, and P
INPB
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
–1.2
–1.4
–1.6
–1.8
–40–200 20406080
P
= P
INPA
INPB
P
= P
INPA
P
= P
INPA
INPB
FREQUENCY – MHz
= P
INPA
TEMPERATURE – ⴗC
INPB
+ 5dB
INPB
– 5dB
1600 1800 2000 22000
–5 dB, P
= P
INPA
= 30 dBm
INPB
85
INPB
,
TPC 14. Change in VMAG Slope vs. Temperature, Three
Sigma to Either Side of Mean, Frequencies 1900 MHz
18
15
12
9
PERCENT
6
3
0
0.800.850.90
MCP – V
0.95
1.00
TPC 16. Center Point of Magnitude Output (MCP) Distribution Frequencies 900 MHz, 17,000 Units
18
15
12
9
PERCENT
6
3
0
27.027.528.028.5
VMAG SLOPE – mV/dB
29.0
29.530.0
TPC 17. VMAG Slope, Frequency 900 MHz, 17,000 Units
25
20
15
10
5
0
–5
VMAG – mV
–10
–15
–20
–25
–40 –30 –20 –10 0 10 20
TEMPERATURE – ⴗC
30 40 50 60
70 80 90
TPC 15. Change in Center Point of Magnitude Output
(MCP) vs. Temperature, Three Sigma to Either Side of
Mean Frequencies 1900 MHz
–8–
0.032
0.030
0.028
SLOPE OF VMAG – V
0.026
0.024
0
200
400
600
800
1000
1200
1400
FREQUENCY – MHz
TPC 18. VMAG Slope vs. Frequency
1600
1800
2000
2200
2400
2600
REV. 0
2800
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