a
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
LF–2.7 GHz
RF/IF Gain and Phase Detector
AD8302
FUNCTIONAL BLOCK DIAGRAM
AD8302
VIDEO OUTPUT – A
INPA
OFSA
60dB LOG AMPS
(7 DETECTORS)
+
–
+
–
VMAG
MFLT
MSET
COMM
PHASE
DETECTOR
PSET
OFSB
INPB
60dB LOG AMPS
(7 DETECTORS)
+
VIDEO OUTPUT – B
–
VPHS
PFLT
1.8V
x3
VREF
VPOS
BIAS
PRODUCT DESCRIPTION
The AD8302 is a 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 controller mode to
force the 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 dis-
abled, 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 avail-
able 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, high
performance 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.
B
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may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices.
V
VMAG shorted MSET,
AD8302–SPECIFICATIONS
(T = 25 C, = P= 5 V,unless otherwisetonoted.)VPHS shorted to PSET, 52.3
resistors connected to INPA and INPB, for Phase measurement P
,
A
S
INPA
INPB
shunt
Unit
MHz
dB
Degree
V
kΩ pF
dBV
dBm
dBV
dBm
mV
V
mV
mA
MHz
V/µs
ns
ns
ns
mV
V
mV
mA
V/µs
MHz
ns
ns
dB
dB
dB
mV/dB
dB
dB
dB
Degree
Degree
mV/Degree
Degree
Degree
Parameter
OVERALL FUNCTION
Input Frequency Range
Gain Measurement Range
Phase Measurement Range
Reference Voltage Output
INPUT INTERFACE
Input Simplified Equivalent Circuit
Input Voltage Range
Center of Input Dynamic Range
MAGNITUDE OUTPUT
Output Voltage Minimum
Output Voltage Maximum
Center Point of Output (MCP)
Output Current
Small Signal Envelope Bandwidth
Slew Rate
Response Time
Rise Time
Fall Time
Settling Time
PHASE OUTPUT
Output Voltage Minimum
Output Voltage Maximum
Phase Center Point
Output Current Drive
Slew Rate
Small Signal Envelope Bandwidth
Response Time
100 MHz
Dynamic Range
Conditions
Min
>0
Typ
Max
2700
P
IN
at INPA, P
IN
at INPB = –30 dBm
φ
IN
at INPA >
φ
IN
at INPB
Pin VREF, –40°C
≤
T
A
≤
+85°C
Pins INPA and INPB
To AC Ground, f
≤
500 MHz
AC-Coupled (0 dBV = 1 V rms)
re: 50
Ω
1.72
±
30
±
90
1.8
32
1.88
–73
–60
–43
–30
–13
0
Pin VMAG
20
×
Log (V
INPA
/V
INPB
) = –30 dB
20
×
Log (V
INPA
/V
INPB
) = +30 dB
V
INPA
= V
INPB
Source/Sink
Pin MFLT Open
40 dB Change, Load 20 pF 10 kΩ
Any 20 dB Change, 10%–90%
Any 20 dB Change, 90%–10%
Full-Scale 60 dB Change, to 1% Settling
Pin VPHS
Phase Difference 180 Degrees
Phase Difference 0 Degrees
When
φ
INPA
=
φ
INPB
±
90°
Source/Sink
30
1.8
900
8
30
25
50
60
300
30
1.8
900
8
25
30
40
500
58
55
42
29
0.25
0.25
0.2
145
143
10
0.7
0.7
Any 15 Degree Change, 10%–90%
120 Degree Change C
FILT
= 1 pF, to 1% Settling
MAGNITUDE OUTPUT
±
1 dB Linearity P
REF
= –30 dBm (V
REF
= –43 dBV)
±
0.5 dB Linearity P
REF
= –30 dBm (V
REF
= –43 dBV)
±
0.2 dB Linearity P
REF
= –30 dBm (V
REF
= –43 dBV)
From Linear Regression
Deviation from Output at 25°C
–40°C
≤
T
A
≤
+85°C, P
INPA
= P
INPB
= –30 dBm
Deviation from Best Fit Curve at 25°C
–40°C
≤
T
A
≤
+85°C, P
INPA
=
±
25 dB, P
INPB
= –30 dBm
P
INPA
= P
INPB
= –5 dBm to –50 dBm
PHASE OUTPUT
Less than
±
1 Degree Deviation from Best Fit Line
Less than 10% Deviation in Instantaneous Slope
From Linear Regression about –90° or +90°
Deviation from Output at 25°C
–40°C
≤
T
A
≤
+85°C, Delta Phase = 90 Degrees
Deviation from Best Fit Curve at 25°C
–40°C
≤
T
A
≤
+85°C, Delta Phase =
±
30 Degrees
Slope
Deviation vs. Temperature
Gain Measurement Balance
Dynamic Range
Slope (Absolute Value)
Deviation vs. Temperature
–2–
REV.
B
AD8302
Parameter
900 MHz
Dynamic Range
Conditions
MAGNITUDE OUTPUT
±
1 dB Linearity P
REF
= –30 dBm (V
REF
= –43 dBV)
±
0.5 dB Linearity P
REF
= –30 dBm (V
REF
= –43 dBV)
±
0.2 dB Linearity P
REF
= –30 dBm (V
REF
= –43 dBV)
From Linear Regression
Deviation from Output at 25°C
–40°C
≤
T
A
≤
+85°C, P
INPA
= P
INPB
= –30 dBm
Deviation from Best Fit Curve at 25°C
–40°C
≤
T
A
≤
+85°C, P
INPA
=
±
25 dB, P
INPB
= –30 dBm
P
INPA
= P
INPB
= –5 dBm to –50 dBm
PHASE OUTPUT
Less than
±
1 Degree Deviation from Best Fit Line
Less than 10% Deviation in Instantaneous Slope
From Linear Regression about –90° or +90°
Linear Deviation from Best Fit Curve at 25°C
–40°C
≤
T
A
≤
+85°C, Delta Phase = 90 Degrees
–40°C
≤
T
A
≤
+85°C, Delta Phase =
±
30 Degrees
Phase @ INPA = Phase @ INPB, P
IN
= –5 dBm to –50 dBm
MAGNITUDE OUTPUT
±
1 dB Linearity P
REF
= –30 dBm (V
REF
= –43 dBV)
±
0.5 dB Linearity P
REF
= –30 dBm (V
REF
= –43 dBV)
±
0.2 dB Linearity P
REF
= –30 dBm (V
REF
= –43 dBV)
From Linear Regression
Deviation from Output at 25°C
–40°C
≤
T
A
≤
+85°C, P
INPA
= P
INPB
= –30 dBm
Deviation from Best Fit Curve at 25°C
–40°C
≤
T
A
≤
+85°C, P
INPA
=
±25
dB, P
INPB
= –30 dBm
P
INPA
= P
INPB
= –5 dBm to –50 dBm
PHASE OUTPUT
Less than
±
1 Degree Deviation from Best Fit Line
Less than 10% Deviation in Instantaneous Slope
From Linear Regression about –90° or +90°
Linear Deviation from Best Fit Curve at 25°C
–40°C
≤
T
A
≤
+85°C, Delta Phase = 90 Degrees
–40°C
≤
T
A
≤
+85°C, Delta Phase =
±
30 Degrees
Phase @ INPA = Phase @ INPB, P
IN
= –5 dBm to –50 dBm
MAGNITUDE OUTPUT
±
1 dB Linearity P
REF
= –30 dBm (V
REF
= –43 dBV)
±
0.5 dB Linearity P
REF
= –30 dBm (V
REF
= –43 dBV)
±
0.2 dB Linearity P
REF
= –30 dBm (V
REF
= –43 dBV)
From Linear Regression
Deviation from Output at 25°C
–40°C
≤
T
A
≤
+85°C, P
INPA
= P
INPB
= –30 dBm
Deviation from Best Fit Curve at 25°C
–40°C
≤
T
A
≤
+85°C, P
INPA
=
±
25 dB, P
INPB
= –30 dBm
P
INPA
= P
INPB
= –5 dBm to –50 dBm
PHASE OUTPUT
Less than
±
1 Degree Deviation from Best Fit Line
Less than 10% Deviation in Instantaneous Slope
From Linear Regression about –90° or +90°
Linear Deviation from Best Fit Curve at 25°C
–40°C
≤
T
A
≤
+85°C, Delta Phase = 90 Degrees
–40°C
≤
T
A
≤
+85°C, Delta Phase =
±
30 Degrees
Pin VREF
Load = 2 kΩ
V
S
= 2.7 V to 5.5 V
Source/Sink (Less than 1% Change)
Pin VPOS
2.7
V
S
= 5 V
–40°C
≤
T
A
≤
+85°C
5.0
19
21
5.5
25
27
V
mA
mA
1.7
Min
Typ
58
54
42
28.7
0.25
0.25
0.2
143
143
10.1
0.75
0.75
0.8
57
54
42
27.5
0.27
0.33
0.2
128
120
10.2
0.8
0.8
1
53
51
38
27.5
0.28
0.4
0.2
115
110
10
0.85
0.9
1.8
0.25
5
1.9
Max
Unit
dB
dB
dB
mV/dB
dB
dB
dB
Degree
Degree
mV/Degree
Degree
Degree
Slope
Deviation vs. Temperature
Gain Measurement Balance
Dynamic Range
Slope (Absolute Value)
Deviation
Phase Measurement Balance
1900 MHz
Dynamic Range
Degree
dB
dB
dB
mV/dB
dB
dB
dB
Degree
Degree
mV/Degree
Degree
Degree
Degree
dB
dB
dB
mV/dB
dB
dB
dB
Degree
Degree
mV/Degree
Degree
Degree
V
mV/V
mA
Slope
Deviation vs. Temperature
Gain Measurement Balance
Dynamic Range
Slope (Absolute Value)
Deviation
Phase Measurement Balance
2200 MHz
Dynamic Range
Slope
Deviation vs. Temperature
Gain Measurement Balance
Dynamic Range
Slope (Absolute Value)
Deviation
REFERENCE VOLTAGE
Output Voltage
PSRR
Output Current
POWER SUPPLY
Supply
Operating Current (Quiescent)
Specifications subject to change without notice.
REV.
B
–3–
AD8302
ABSOLUTE MAXIMUM RATINGS
1
PIN CONFIGURATION
COMM
1
INPA
2
OFSA
3
VPOS
4
14
13
Supply Voltage V
S
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 V
PSET, MSET Voltage . . . . . . . . . . . . . . . . . . . . . . V
S
+ 0.3 V
INPA, INPB Maximum Input . . . . . . . . . . . . . . . . . . –3 dBV
Equivalent Power Re. 50
Ω
. . . . . . . . . . . . . . . . . . 10 dBm
θ
JA2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150°C/W
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 perma-
nent 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.
MFLT
VMAG
MSET
AD8302
12
TOP VIEW
11
VREF
(Not to Scale)
10
PSET
OFSB
5
INPB
6
9
8
VPHS
PFLT
COMM
7
PIN FUNCTION DESCRIPTIONS
Pin No.
1, 7
2
3
4
5
6
8
9
10
11
12
13
14
Mnemonic
COMM
INPA
OFSA
VPOS
OFSB
INPB
PFLT
VPHS
PSET
VREF
MSET
VMAG
MFLT
Function
Device Common. Connect to low impedance ground.
High Input Impedance to Channel A. Must be ac-coupled.
A capacitor to ground at this pin sets the offset compensation filter corner
and provides input decoupling.
Voltage Supply (V
S
), 2.7 V to 5.5 V
A capacitor to ground at this pin sets the offset compensation filter corner
and provides input decoupling.
Input to Channel B. Same structure as INPA.
Low Pass Filter Terminal for the Phase Output
Single-Ended Output Proportional to the Phase Difference between INPA
and INPB.
Feedback Pin for Scaling of VPHS Output Voltage in Measurement Mode.
Apply a setpoint voltage for controller mode.
Internally Generated Reference Voltage (1.8 V Nominal)
Feedback Pin for Scaling of VMAG Output Voltage Measurement Mode.
Accepts a set point voltage in controller mode.
Single-Ended Output. Output voltage proportional to the decibel ratio
of signals applied to INPA and INPB.
Low Pass Filter Terminal for the Magnitude Output
Equivalent
Circuit
Circuit A
Circuit A
Circuit A
Circuit A
Circuit E
Circuit B
Circuit D
Circuit C
Circuit D
Circuit B
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.
WARNING!
ESD SENSITIVE DEVICE
–4–
REV.
B
AD8302
VPOS
VPOS
100mV
4k
INPA(INPB)
4k
OFSA(OFSB)
10pF
+
ON TO
LOG-AMP
–
750
CLASS A-B
CONTROL
25
VMAG
(VPHS)
2k
COMM
COMM
Circuit A
Circuit B
VPOS
VPOS
VPOS
VREF
10k
5k
MSET
(PSET)
10k
MFLT
(PFLT)
1.5pF
ACTIVE LOADS
10k
COMM
COMM
COMM
Circuit C
Circuit D
Figure 1. Equivalent Circuits
Circuit E
REV.
B
–5–