FUNCTIONAL BLOCK DIAGRAM
AN
IFN
VP
IFP
AP
GND
VN
RFP
RFN
VN
VP
LON
LOP
VP
GND
BIAS
VN
OUT
VFB
COM
AD831
50
50
13
9
10
11
12
6
7
8
4
5
14
15
16
17
18
1
2
3
19
20
REV. B
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
a
Low Distortion Mixer
AD831
FEATURES
Doubly-Balanced Mixer
Low Distortion
+24 dBm Third Order Intercept (IP3)
+10 dBm 1 dB Compression Point
Low LO Drive Required: 10 dBm
Bandwidth
500 MHz RF and LO Input Bandwidths
250 MHz Differential Current IF Output
DC to >200 MHz Single-Ended Voltage IF Output
Single or Dual Supply Operation
DC Coupled Using Dual Supplies
All Ports May Be DC Coupled
No Lower Frequency Limit--Operation to DC
User-Programmable Power Consumption
APPLICATIONS
High Performance RF/IF Mixer
Direct to Baseband Conversion
Image-Reject Mixers
I/Q Modulators and Demodulators
PRODUCT DESCRIPTION
The AD831 is a low distortion, wide dynamic range, monolithic
mixer for use in such applications as RF to IF down conversion
in HF and VHF receivers, the second mixer in DMR base sta-
tions, direct-to-baseband conversion, quadrature modula-
tion and demodulation, and doppler-shift detection in ultra-
sound imaging applications. The mixer includes an LO driver
and a low-noise output amplifier and provides both user-pro-
grammable power consumption and 3rd-order intercept point.
The AD831 provides a +24 dBm third-order intercept point for
10 dBm LO power, thus improving system performance and
reducing system cost compared to passive mixers, by eliminating
the need for a high power LO driver and its attendant shielding
and isolation problems.
The RF, IF, and LO ports may be dc or ac coupled when the
mixer is operating from
5 V supplies or ac coupled when oper-
ating from a single supply of 9 V minimum. The mixer operates
with RF and LO inputs as high as 500 MHz.
The mixer's IF output is available as either a differential current
output or a single-ended voltage output. The differential output
is from a pair of open collectors and may be ac coupled via a
transformer or capacitor to provide a 250 MHz output band-
width. In down-conversion applications, a single capacitor con-
nected across these outputs implements a low-pass filter to
reduce harmonics directly at the mixer core, simplifying output
filtering. When building a quadrature-amplitude modulator or
image reject mixer, the differential current outputs of two
AD831s may be summed by connecting them together.
An integral low noise amplifier provides a single-ended voltage
output and can drive such low impedance loads as filters, 50
amplifier inputs, and A/D converters. Its small signal bandwidth
exceeds 200 MHz. A single resistor connected between pins
OUT and FB sets its gain. The amplifier's low dc offset allows
its use in such direct-coupled applications as direct-to-baseband
conversion and quadrature-amplitude demodulation.
The mixer's SSB noise figure is 10.3 dB at 70 MHz using its
output amplifier and optimum source impedance. Unlike pas-
sive mixers, the AD831 has no insertion loss and does not re-
quire an external diplexer or passive termination.
A programmable-bias feature allows the user to reduce power
consumption, with a reduction in the 1 dB compression point
and third-order intercept. This permits a tradeoff between dy-
namic range and power consumption. For example, the AD831
may be used as a second mixer in cellular and two-way radio
base stations at reduced power while still providing a substantial
performance improvement over passive solutions.
PRODUCT HIGHLIGHTS
1. 10 dBm LO Drive for a +24 dBm Output Referred Third
Order Intercept Point
2. Single-Ended Voltage Output
3. High Port-to-Port Isolation
4. No Insertion Loss
5. Single or Dual Supply Operation
6. 10.3 dB Noise Figure
Analog Devices, Inc., 1995
One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
AD831SPECIFICATIONS
Parameter
Conditions
Min
Typ
Max
Units
RF INPUT
Bandwidth
10 dBm Signal Level, IP3
+20 dBm
400
MHz
10.7 MHz IF and High Side Injection
See Figure 1
1 dB Compression Point
10
dBm
Common-Mode Range
1
V
Bias Current
DC Coupled
160
500
A
DC Input Resistance
Differential or Common Mode
1.3
k
Capacitance
2
pF
IF OUTPUT
Bandwidth
Single-Ended Voltage Output, 3 dB
Level = 0 dBm,
R
L
= 100
200
MHz
Conversion Gain
Terminals OUT and VFB Connected
0
dB
Output Offset Voltage
DC Measurement; LO Input Switched
1
40
15
+40
mV
Slew Rate
300
V/
s
Output Voltage Swing
R
L
= 100
, Unity Gain
1.4
V
Short Circuit Current
75
mA
LO INPUT
Bandwidth
10 dBm Input Signal Level
400
MHz
10.7 MHz IF and High Side Injection
Maximum Input Level
1
+1
V
Common-Mode Range
1
+1
V
Minimum Switching Level
Differential Input Signal
200
mV p-p
Bias Current
DC Coupled
17
50
A
Resistance
Differential or Common Mode
500
Capacitance
2
pF
ISOLATION BETWEEN PORTS
LO to RF
LO = 100 MHz, R
S
= 50
, 10.7 MHz IF
70
dB
LO to IF
LO = 100 MHz, R
S
= 50
, 10.7 MHz IF
30
dB
RF to IF
RF = 100 MHz, R
S
= 50
, 10.7 MHz IF
45
dB
DISTORTION AND NOISE
LO = 10 dBm, f = 100 MHz, IF = 10.7 MHz
3rd Order Intercept
Output Referred,
100 mV LO Input
24
dBm
2rd Order Intercept
Output Referred,
100 mV LO Input
62
dBm
1 dB Compression Point
R
L
= 100
, R
BIAS
=
10
dBm
Noise Figure, SSB
Matched Input, RF = 70 MHz, IF = 10.7 MHz
10.3
dB
Matched Input, RF = 150 MHz, IF = 10.7 MHz
14
dB
POWER SUPPLIES
Recommended Supply Range
Dual Supply
4.5
5.5
V
Single Supply
9
11
V
Quiescent Current
1
For Best 3rd Order Intercept Point Performance
100
125
mA
BIAS Pin Open Circuited
NOTES
1
Quiescent current is programmable.
Specifications subject to change without notice.
REV. B
2
(T
A
= +25 C and V
S
= 5 V unless otherwise noted;
all values in dBm assume 50 load.)
AD831
REV. B
3
PIN CONFIGURATION
20-Lead PLCC
PIN DESCRIPTION
Pin
Mnemonic
Description
1
VP
Positive Supply Input
2
IFN
Mixer Current Output
3
AN
Amplifier Negative Input
4
GND
Ground
5
VN
Negative Supply Input
6
RFP
RF Input
7
RFN
RF Input
8
VN
Negative Supply Input
9
VP
Positive Supply Input
10
LON
Local Oscillator Input
11
LOP
Local Oscillator Input
12
VP
Positive Supply Input
13
GND
Ground
14
BIAS
Bias Input
15
VN
Negative Supply Input
16
OUT
Amplifier Output
17
VFB
Amplifier Feedback Input
18
COM
Amplifier Output Common
19
AP
Amplifier Positive Input
20
IFP
Mixer Current Output
WARNING!
ESD SENSITIVE DEVICE
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 AD831 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.
ABSOLUTE MAXIMUM RATINGS
1
Supply Voltage
V
S
. . . . . . . . . . . . . . . . . . . . . . . . . .
5.5 V
Input Voltages
RFHI, RFLO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 V
LOHI, LOLO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 V
Internal Power Dissipation
2
. . . . . . . . . . . . . . . . . . 1200 mW
Operating Temperature Range
AD831A . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 and 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
Thermal Characteristics:
20-Pin PLCC Package:
JA
= 110
C/Watt;
JC
= 20
C/Watt.
Note that the
JA
= 110
C/W value is for the package measured while suspended
in still air; mounted on a PC board, the typical value is
JA
= 90
C/W due to the
conduction provided by the AD83
1
's package being in contact with the board,
which serves as a heat sink.
ORDERING GUIDE
Temperature
Package
Package
Model
Range
Description
Option
AD831AP
40
C to +85
C
20-Lead PLCC
P-20A
GND
VN
VN
RFP
RFN
AN
IFN
AP
VP
IFP
VP
LON
GND
LOP
VP
COM
VFB
BIAS
OUT
VN
19
3
1
2
20
4
5
8
6
7
12 13
9
11
10
18
17
14
16
15
TOP VIEW
(Not to Scale)
AD831
4
REV. B
AD831Typical Characteristics
FREQUENCY MHz
65
64
60
63
62
61
10
1000
100
SECOND ORDER INTERCEPT dBm
Figure 4. Second-Order Intercept vs. Frequency
FREQUENCY MHz
90
70
0
50
30
20
10
80
60
40
10
1000
100
ISOLATION dB
Figure 5. LO-to-RF Isolation vs. Frequency
FREQUENCY MHz
80
70
0
40
30
20
10
50
60
10
1000
100
ISOLATION dB
3 x RF-to-IF
2 x RF-to-IF
RF-to-IF
3 x RF-to-IF
2 x RF-to-IF
RF-to-IF
Figure 6. RF-to-IF Isolation vs. Frequency
FREQUENCY MHz
30
25
0
10
1000
100
THIRD ORDER INTERCEPT dBm
20
15
10
5
Figure 1. Third-Order Intercept vs. Frequency,
IF Held Constant at 10.7 MHz
FREQUENCY MHz
80
70
0
60
50
20
10
40
30
10
1000
100
ISOLATION dB
Figure 2. IF-to-RF Isolation vs. Frequency
FREQUENCY MHz
60
50
0
40
30
20
10
10
1000
100
ISOLATION dB
2 x LO-to-IF
3 x LO-to-IF
LO
Figure 3. LO-to-IF Isolation vs. Frequency
AD831
REV. B
5
FREQUENCY MHz
12
10
0
10
1000
100
1dB COMPRESSION POINT dBm
8
6
4
2
Figure 7. 1 dB Compression Point vs. Frequency, Gain = 1
FREQUENCY MHz
12
10
0
10
1000
100
1dB COMPRESSION POINT dBm
8
6
4
2
Figure 8. 1 dB Compression Point vs. RF Input, Gain = 2
FREQUENCY MHz
25
22
10
19
16
13
100
350
250
150
200
300
THIRD ORDER INTERCEPT dBm
MIXER PLUS AMPLIFIER,
G = 1
MIXER OUTPUT
TRANSFORMER
COUPLED PER FIGURE 18
Figure 9. Third-Order Intercept vs. Frequency , LO Held
Constant at 241 MHz
FREQUENCY MHz
1.00
0.50
1.00
0.00
0.25
0.75
0.75
0.25
0.50
10
1000
100
GAIN ERROR dB
Figure 10. Gain Error vs. Frequency, Gain = 1
FREQUENCY MHz
9
8
0
7
6
5
1
4
3
2
10
1000
100
1dB COMPRESSION POINT dBm
Figure 11. 1 dB Compression Point vs. Frequency, Gain = 4
FREQUENCY MHz
1dB COMPRESSION POINT dBm
11
10
7
0
600
100
200
300
400
500
9
8
LO LEVEL = 10dBm
IF = 10.7MHz
V
S
= 8V
V
S
= 9V
Figure 12. Input 1 dB Compression Point vs. Frequency,
Gain = 1, 9 V Single Supply
6
REV. B
AD831Typical Characteristics
FREQUENCY MHz
30
25
15
0
500
50
100
150
200
250
300
350
400
450
20
THIRD ORDER INTERCEPT dBm
LO LEVEL = 10dBm
IF = 10.7MHz
f = 20kHz
V
S
= 8V
V
S
= 9V
Figure 13. Input Third Order Intercept, 9 V Single Supply
FREQUENCY MHz
62.4
61.4
60.8
0
500
50
100
150
200
250
300
350
400
450
62.2
61.6
61.2
61.0
62.0
61.8
60.2
60.6
SECOND ORDER INTERCEPT dBm
60.4
LO LEVEL = 10dBm
IF = 10.7MHz
f = 20kHz
V
S
= 8V
V
S
= 9V
Figure 14. Input Second Order Intercept,
9 V Single Supply
FREQUENCY MHz
1200
1000
0
50
250
100
150
200
800
600
400
200
INPUT RESISTANCE Ohms
4.0
3.5
3.0
2.5
2.0
INPUT CAPACITANCE pF
INPUT RESISTANCE
INPUT CAPACITANCE
Figure 15. Input Impedance vs. Frequency, Z
IN
= R C
FREQUENCY MHz
18
NOISE FIGURE dB
16
8
50
250
100
150
200
15
13
11
9
17
14
12
10
Figure 16. Noise Figure vs. Frequency,
Matched Input
AD831
REV. B
7
THEORY OF OPERATION
The AD831 consists of a mixer core, a limiting amplifier, a low
noise output amplifier, and a bias circuit (Figure 17).
The mixer's RF input is converted into differential currents by a
highly linear, Class A voltage-to-current converter, formed by
transistors Q1, Q2 and resistors R1, R2. The resulting currents
drive the differential pairs Q3, Q4 and Q5, Q6. The LO input is
through a high gain, low noise limiting amplifier that converts
the 10 dBm LO input into a square wave. This square wave
drives the differential pairs Q3, Q4 and Q5, Q6 and produces a
high level output at IFP and IFN--consisting of the sum and
difference frequencies of the RF and LO inputs--and a series of
lower level outputs caused by odd harmonics of the LO fre-
quency mixing with the RF input.
An on-chip network supplies the bias current to the RF and LO
inputs when these are ac coupled; this network is disabled when
the AD831 is dc coupled.
When the integral output amplifier is used, pins IFN and IFP
are connected directly to pins AFN and AFP; the on-chip load
resistors convert the output current into a voltage that drives the
output amplifier. The ratio of these load resistors to resistors
R1, R2 provides nominal unity gain (0 dB) from RF to IF. The
expression for the gain, in decibels, is
G
dB
=
20 log
10
4
1
2
2
Equation 1
where
4
is the amplitude of the fundamental component of a square wave
1
2
is the conversion loss
2
is the small signal dc gain of the AD831 when the LO input
is driven fully positive or negative.
20
2
Q3
R5
1k
LIMITING
AMPLIFIER
16
A
O
17
CURRENT
MIRROR
VP
50
50
20
20
BIAS
18mA TYP
IFN
AN
AP
IFP
19
3
18mA TYP
5k
5k
Q1
Q2
Q5
Q6
Q4
R4
1k
R1
20
R2
20
R3
26
Q7
BIAS
36
50
50
18
OUT
VFB
COM
12mA TYP
36mA TYP
27mA TYP
LOP
LON
RFP
RFN
VP
BIAS
VN
LOCAL
OSCILLATOR
INPUT
RF
INPUT
1
10
11
6
7
BIAS
CURRENT
Figure 17. Simplified Schematic Diagram
AD831
REV. B
8
Low-Pass Filtering
A simple low-pass filter may be added between the mixer and
the output amplifier by shunting the internal resistive loads (an
equivalent resistance of about 14
with a tolerance of 20%)
with external capacitors; these attenuate the sum component in
a down-conversion application (Figure 20). The corner fre-
quency of this one-pole low-pass filter (f = (2
RC
F
)
1
) should
be placed about an octave above the difference frequency IF.
Thus, for a 70 MHz IF, a 3 dB frequency of 140 MHz might
be chosen, using C
F
= (2
14
140 MHz)
1
82 pF, the
nearest standard value.
IFN
VP
IFP
AP
GND
VN
RFP
RFN
VN
VP
LON
LOP
VP
GND
BIAS
VN
AD831
Top View
50
50
6
7
8
4
5
9
10
11
12
13
AN
VFB
COM
OUT
14
15
16
17
18
1
2
3
19
20
C
F
C
F
C
F
= =
1
2
f R
1
89.7 f
Figure 20. Low-Pass Filtering Using External Capacitors
Using the Output Amplifier
The AD831's output amplifier converts the mixer core's dif-
ferential current output into a single-ended voltage and provides
an output as high as
1 V peak into a 50
load (+10 dBm).
For unity gain operation (Figure 21), the inputs AN and AP
connect to the open-collector outputs of the mixer's core and
OUT connects to VFB.
IF
OUTPUT
IFN
VP
IFP
AP
GND
VN
RFP
RFN
VN
VP
LON
LOP
VP
GND
BIAS
VN
AD831
Top View
50
50
6
7
8
4
5
9
10
11
12
13
AN
VFB
COM
OUT
14
15
16
17
18
1
2
3
19
20
Figure 21. Output Amplifier Connected for Unity Gain
Operation
The mixer has two open-collector outputs (differential cur-
rents) at pins IFN and IFP. These currents may be used to pro-
vide nominal unity RF-to-IF gain by connecting a center-tapped
transformer (1:1 turns ratio) to pins IFN and IFP as shown in
Figure 18.
20
2
Q3
R5
1k
LIMITING
AMPLIFIER
VP
18mA TYP
IFN
IFP
18mA TYP
5k
5k
Q1
Q2
Q5
Q6
Q4
R4
1k
R1
20
R2
20
R3
26
Q7
36mA TYP
LOP
LON
RFP
RFN
VP
BIAS
VN
LOCAL
OSCILLATOR
INPUT
RF
INPUT
1
10
11
6
7
BIAS
CURRENT
IF OUTPUT
VPOS
MCLT4-1H
Figure 18. Connections for Transformer Coupling to the IF
Output
Programming the Bias Current
Because the AD831's RF port is a Class-A circuit, the maxi-
mum RF input is proportional to the bias current. This bias cur-
rent may be reduced by connecting a resistor from the BIAS pin
to the positive supply (Figure 19). For normal operation, the
BIAS pin is left unconnected. For lowest power consumption,
the BIAS pin is connected directly to the positive supply. The
range of adjustment is 100 mA for normal operation to
45 mA total current at minimum power consumption.
1.33k
0.1F
VPOS
NOTE ADDED
RESISTOR
IFN
VP
IFP
AP
GND
VN
RFP
RFN
VN
VP
LON
LOP
VP
GND
BIAS
VN
AD831
Top View
50
50
6
7
8
4
5
9
10
11
12
13
AN
VFB
COM
OUT
14
15
16
17
18
1
2
3
19
20
Figure 19. Programming the Quiescent Current
AD831
REV. B
9
For gains other than unity, the amplifier's output at OUT is
connected via an attenuator network to VFB; this determines
the overall gain. Using resistors R1 and R2 (Figure 22), the gain
setting expression is
G
dB
=
20 log
10
R1
+
R2
R2
Equation 2
R2
R1
IF
OUTPUT
IFN
VP
IFP
AP
GND
VN
RFP
RFN
VN
VP
LON
LOP
VP
GND
BIAS
VN
AD831
Top View
50
50
6
7
8
4
5
9
10
11
12
13
AN
VFB
COM
OUT
14
15
16
17
18
1
2
3
19
20
Figure 22. Output Amplifier Feedback Connections for
Increasing Gain
Driving Filters
The output amplifier can be used for driving reverse-terminated
loads. When driving an IF bandpass filter (BPF), for example,
proper attention must be paid to providing the optimal source
and load terminations so as to achieve the specified filter re-
sponse. The AD831's wideband highly linear output amplifier
affords an opportunity to increase the RF-to-IF gain to compen-
sate for a filter's insertion and termination losses.
Figure 23 indicates how the output amplifier's low impedance
(voltage source) output can drive a doubly-terminated bandpass
filter. The typical 10 dB of loss (4 dB of insertion loss and 6 dB
due to the reverse-termination) be made up by the inclusion of a
feedback network that increases the gain of the amplifier by
10 dB (
3.162). When constructing a feedback circuit, the sig-
nal path between OUT and VFB should be as short as possible.
R2
51.1
R1
110
IF
OUTPUT
IFN
VP
IFP
AP
GND
VN
RFP
RFN
VN
VP
LON
LOP
VP
GND
BIAS
VN
AD831
Top View
50
50
6
7
8
4
5
9
10
11
12
13
AN
VFB
COM
OUT
14
15
16
17
18
1
2
3
19
20
R
T
BPF
R
T
Figure 23. Connections for Driving a Doubly-Terminated
Bandpass Filter
Higher gains can be achieved, using different resistor ratios, but
with concomitant reduction in the bandwidth of this amplifier
(Figure 24). Note also that the Johnson noise of these gain-set-
ting resistors, as well as that of the BPF terminating resistors, is
ultimately reflected back to the mixer's input; thus they should
be as small as possible, consistent with the permissible loading
on the amplifier's output.
FREQUENCY MHz
12
10
0
10
1000
100
1dB COMPRESSION POINT dBm
8
6
4
2
G = 1
G = 2
G = 4
Figure 24. Output Amplifier 1 dB Compression Point for
Gains of 1, 2, and 4 (Gains of 0 dB, 6 dB, and 12 dB,
Respectively)
AD831
REV. B
10
The RF input to the AD831 is shown connected by an imped-
ance matching network for an assumed source impedance of
50
. Figure 15 shows the input impedance of the AD831 plot-
ted vs. frequency. The input circuit can be modeled as a resis-
tance in parallel with a capacitance. The 82 pF capacitors (C
F
)
connected from IFN and IFP to VP provide a low-pass filter
with a cutoff frequency of approximately 140 MHz in down-
conversion applications (see the Theory of Operation section of
this data sheet for more details). The LO input is connected
single-ended because the limiting amplifier provides a symmet-
ric drive to the mixer. To minimize intermodulation distortion,
connect pins OUT and VFB by the shortest possible path. The
connections shown are for unity-gain operation.
At LO frequencies less than 100 MHz, the AD831's LO power
may be as low as 20 dBm for satisfactory operation. Above
100 MHz, the specified LO power of 10 dBm must be used.
51.1
110
IF
OUTPUT
R
T
BPF
R
T
NC
5V
0.1F
0.1F
+5V
51.1
0.1F
+5V
5V
0.1F
5V
0.1F
C2
L1
C1
RF
INPUT
C
F
82pF
C
F
82pF
0.1F
+5V
IFN
VP
IFP
AP
GND
VN
RFP
RFN
VN
VP
LON
LOP
VP
GND
BIAS
VN
AD831
Top View
50
50
6
7
8
4
5
9
10
11
12
13
AN
VFB
COM
OUT
14
15
16
17
18
1
2
3
19
20
LO INPUT
10 dBm
Figure 25. Connections for
5 V Dual-Supply Operation Showing Impedance
Matching Network and Gain of 2 for Driving Reverse-Terminated IF Filter
APPLICATIONS
Careful component selection, circuit layout, power supply
decoupling, and shielding are needed to minimize the AD831's
susceptibility to interference from radio and TV stations, etc. In
bench evaluation, we recommend placing all of the components
in a shielded box and using feedthrough decoupling networks
for the supply voltage.
Circuit layout and construction are also critical, since stray ca-
pacitances and lead inductances can form resonant circuits and
are a potential source of circuit peaking, oscillation, or both.
Dual-Supply Operation
Figure 25 shows the connections for dual supply operation.
Supplies may be as low as
4.5 V but should be no higher than
5.5 V due to power dissipation.
AD831
REV. B
11
Single Supply Operation
Figure 26 is similar to the dual supply circuit in Figure 19. Sup-
plies may be as low as 9 V but should not be higher than
11 V due to power dissipation. As in Figure 19, both the RF
and LO ports are driven single-ended and terminated.
In single supply operation, the COM terminal is the "ground"
reference for the output amplifier and must be biased to 1/2 the
supply voltage, which is done by resistors R1 and R2. The OUT
pin must be ac-coupled to the load.
R1
110
IF
OUTPUT
R
T
NC
0.1F
0.1F
+9V
51.1
0.1F
+9V
0.1F
C2
L1
C1
RF
INPUT
82pF
82pF
0.1F
+9V
LO INPUT
10 dBm
5k
5k
+5V
R2
51.1
C
C
0.1F
0.1F
IFN
VP
IFP
AP
GND
VN
RFP
RFN
VN
VP
LON
LOP
VP
GND
BIAS
VN
AD831
Top View
50
50
6
7
8
4
5
9
10
11
12
13
AN
VFB
COM
OUT
14
15
16
17
18
1
2
3
19
20
Figure 26. Connections for
+9 V Single-Supply Operation
AD831
REV. B
12
Connections Quadrature Demodulation
Two AD831 mixers may have their RF inputs connected in par-
allel and have their LO inputs driven in phase quadrature (Fig-
ure 27) to provide demodulated in-phase (I) and quadrature
(Q) outputs. The mixers' inputs may be connected in parallel
and a single termination resistor used if the mixers are located in
close proximity on the PC board.
DEMODULATED
QUADRATURE
OUTPUT
NC
5V
0.1F
0.1F
+5V
51.1
0.1F
+5V
5V
0.1F
5V
0.1F
IF
INPUT
C
F
C
F
0.1F
+5V
IFN
VP
IFP
AP
GND
VN
RFP
RFN
VN
VP
LON
LOP
VP
GND
BIAS
VN
AD831
Top View
50
50
6
7
8
4
5
9
10
11
12
13
AN
VFB
COM
OUT
14
15
16
17
18
1
2
3
19
20
LO INPUT
AT 90
10 dBm
DEMODULATED
IN-PHASE
OUTPUT
NC
5V
0.1F
0.1F
+5V
51.1
0.1F
+5V
5V
0.1F
5V
0.1F
C
F
C
F
0.1F
+5V
LO INPUT
AT 0
10 dBm
51.1
IFN
VP
IFP
AP
GND
VN
RFP
RFN
VN
VP
LON
LOP
VP
GND
BIAS
VN
AD831
Top View
50
50
6
7
8
4
5
9
10
11
12
13
AN
VFB
COM
OUT
14
15
16
17
18
1
2
3
19
20
Figure 27. Connections for Quadrature Demodulation
AD831
REV. B
13
Table I. AD831 Mixer Table, 4.5 V Supplies, LO = 9 dBm
LO Level
9.0 dBm, LO Frequency 130.7 MHz, Data File imdTB10771
RF Level
0.0 dBm, RF Frequency 120 MHz
Temperature Ambient
Dut Supply
4.50 V
VPOS Current
90 mA
VNEG Current
91 mA
Intermodulation Table RF harmonics (rows)
LO harmonics (columns).
First row absolute value of nRF-mLO, and second row is the sum.
0
1
2
3
4
5
6
7
0
32.7
35.7
21.1
11.6
19.2
35.1
41.9
32.7
35.7
21.1
11.6
19.2
35.1
41.9
1
31.6
0.0
37.2
41.5
30.4
34.3
25.2
40.1
31.6
28.5
26.7
28.0
27.2
33.2
34.3
44.8
2
45.3
48.2
39.4
57.6
44.9
42.4
40.2
40.2
45.3
42.4
49.4
42.5
51.1
46.2
58.1
61.6
3
54.5
57.1
57.5
50.6
62.6
55.8
59.7
55.2
54.5
65.5
46.0
63.7
60.6
69.6
72.7
73.5
4
67.1
63.1
69.9
69.9
69.6
74.1
69.7
58.6
67.1
53.6
72.9
71.2
70.1
72.6
73.5
72.7
5
53.5
62.6
73.8
72.3
70.7
71.1
74.3
73.0
53.5
68.4
70.8
72.8
73.4
73.2
73.3
72.5
6
73.6
57.7
68.6
73.1
73.8
73.0
72.9
74.4
73.6
73.5
72.7
73.5
73.6
73.1
72.4
73.7
7
73.8
73.9
63.4
72.6
74.6
74.9
73.6
74.5
73.8
73.8
73.2
73.8
72.6
73.7
73.5
72.9
Table II. AD831 Mixer Table, 5 V Supplies, LO = 9 dBm
LO Level
9.0 dBm, LO Frequency 130.7 MHz, Data File imdTB13882
RF Level
0.0 dBm, RF Frequency 120 MHz
Temperature Ambient
Dut Supply
5.00 V
VPOS Current
102 mA
VNEG Current
102 mA
Intermodulation table RF harmonics (rows)
LO harmonics (columns).
First row absolute value of nRF-mLO, and second row is the sum.
0
1
2
3
4
5
6
7
0
36.5
46.5
33.0
17.0
23.0
34.2
45.6
36.5
46.5
33.0
17.0
23.0
34.2
45.6
1
37.5
0.0
41.2
41.1
38.5
29.0
31.7
47.4
37.5
29.1
38.7
22.9
28.4
35.3
34.3
52.4
2
45.9
45.2
47.6
61.5
53.7
43.5
41.5
41.8
45.9
39.4
35.7
38.4
42.3
53.7
52.8
66.3
3
46.4
53.0
67.0
43.0
60.9
47.9
50.7
41.0
46.4
40.0
50.0
48.9
57.8
57.0
71.8
67.4
4
45.1
56.0
48.7
64.6
53.5
55.7
53.5
51.1
45.1
39.0
48.1
58.4
56.1
63.8
70.5
67.6
5
35.2
45.3
54.1
54.1
53.7
57.9
66.6
64.3
35.2
53.0
62.4
67.3
67.0
69.4
73.2
72.9
6
63.4
41.1
53.6
66.5
58.8
63.3
61.7
71.4
63.4
66.3
67.2
67.5
72.9
71.2
71.7
73.2
7
67.3
65.8
37.8
54.6
62.5
71.7
55.2
57.1
67.3
61.6
66.3
72.9
71.4
70.7
72.1
73.1
AD831
REV. B
14
Table III. AD831 Mixer Table, 3.5 V Supplies, LO = 20 dBm
LO Level
20.0 dBm, LO Frequency 130.7 MHz, Data File G1T1K 0771
RF Level
0.0 dBm, RF Frequency 120 MHz
Temperature Ambient
Dut Supply
3.50 V
VPOS Current
55 mA
VNEG Current
57 mA
Intermodulation Table RF harmonics (rows)
LO harmonics (columns).
First row absolute value of nRF-mLO, and second row is the sum.
0
1
2
3
4
5
6
7
0
45.2
35.7
16.1
21.6
22.3
32.0
36.4
45.2
35.7
16.1
21.6
22.3
32.0
36.4
1
30.3
0.0
33.7
47.9
37.5
33.8
32.0
45.2
30.3
29.7
28.2
24.4
26.0
47.4
35.9
49.7
2
50.3
49.4
47.4
49.9
48.8
38.5
40.7
51.0
50.3
41.0
51.4
34.7
49.8
48.6
68.5
67.9
3
48.4
55.7
58.2
45.0
57.0
68.4
55.5
47.7
48.4
52.9
50.0
64.5
62.8
73.4
74.0
71.8
4
66.7
59.7
67.2
62.8
58.2
71.5
72.9
63.5
66.7
65.9
78.1
74.2
77.5
74.4
77.9
77.5
5
66.9
71.5
73.6
77.6
70.8
70.2
75.8
78.1
66.9
76.3
78.1
78.2
78.1
78.0
77.9
77.9
6
78.0
69.7
76.7
78.6
78.8
75.4
78.1
79.0
78.0
78.3
78.3
78.2
78.1
78.0
77.9
77.8
7
78.4
78.5
76.9
78.7
79.0
79.1
78.6
78.9
78.4
78.3
78.2
78.2
77.9
77.9
77.8
77.5
Table IV. AD831 Mixer Table, 5 V Supplies, 1 k Bias Resistor, LO = 20 dBm
LO Level
20.0 dBm, LO Frequency 130.7 MHz, Data File G1T1K 3881
RF Level
0.0 dBm, RF Frequency 120 MHz
Temperature Ambient
Dut Supply
3.50 V
VPOS Current
59 mA
VNEG Current
61 mA
Intermodulation table RF harmonics (rows)
LO harmonics (columns).
First row absolute value of nRF-mLO, and second row is the sum.
0
1
2
3
4
5
6
7
0
60.6
52.3
16.6
12.8
26.0
45.0
38.8
60.6
52.3
16.6
12.8
26.0
45.0
38.8
1
34.1
0.0
35.2
41.8
29.8
29.1
35.3
49.0
34.1
27.3
28.7
20.7
32.9
39.2
38.2
47.8
2
46.6
48.8
40.1
52.2
57.9
38.6
45.8
47.7
46.6
37.8
47.6
41.7
54.2
50.4
64.1
64.9
3
41.3
58.8
59.5
41.8
61.2
58.1
57.5
54.0
41.3
47.9
65.2
62.5
64.2
73.8
72.3
72.6
4
53.9
52.5
73.7
68.1
60.3
71.0
63.4
62.3
53.9
61.4
70.6
76.9
76.8
78.6
78.3
78.1
5
66.9
65.8
76.6
75.2
65.4
70.0
73.6
68.7
66.9
69.7
72.9
77.4
77.7
78.5
78.4
78.2
6
77.4
73.3
73.8
78.8
79.2
73.6
74.9
79.3
77.4
78.6
78.7
78.6
78.6
78.4
78.2
78.2
7
78.9
79.0
77.9
78.0
79.3
79.5
79.3
79.3
78.9
78.8
78.7
78.6
78.3
78.3
78.1
78.0
AD831
REV. B
15
5V
+5V
MCL
ZFSC-2-1
COMBINER
LO
50
AD831
PER
FIGURE 25
HP 6632A
PROGRAMMABLE
POWER SUPPLY
HP 6632A
PROGRAMMABLE
POWER SUPPLY
HP 9920
IEEE CONTROLLER
HP 9121
DISK DRIVE
FLUKE 6082A
SYNTHESIZED
SIGNAL GENERATOR
HP 8561E
SPECTRUM
ANALYZER
IEEE-488 BUS
HP 8656B
SYNTHESIZED
SIGNAL GENERATOR
HP 8656A
SYNTHESIZED
SIGNAL GENERATOR
Figure 28. Third-Order Intercept Characterization Setup
5V
+5V
LO
50
AD831
PER
FIGURE 25
HP 8656B
SYNTHESIZED
SIGNAL GENERATOR
MCL
ZFSC-2-1
HP 8656B
SYNTHESIZED
SIGNAL GENERATOR
RF
IF
50
HP 6632A
PROGRAMMABLE
POWER SUPPLY
HP 6632A
PROGRAMMABLE
POWER SUPPLY
50
50
USED FOR
IF TO RF, LO
LO TO RF
MOVE SPECTRUM
ANALYZER FOR IF
MEASUREMENTS
MCL
ZFSC-2-1
HP 8656B
SYNTHESIZED
SIGNAL GENERATOR
HP 8561E
SPECTRUM
ANALYZER
Figure 29. IF to RF Isolation Characterization Setup
AD831
REV. B
16
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
20-Lead PLCC (P-20A)
0.048 (1.21)
0.042 (1.07)
0.356 (9.04)
0.350 (8.89)
SQ
0.395 (10.02)
0.385 (9.78)
SQ
0.048 (1.21)
0.042 (1.07)
0.050
(1.27)
BSC
0.020
(0.50)
R
19
3
TOP VIEW
18
14
9
8
PIN 1
IDENTIFIER
4
13
0.110 (2.79)
0.085 (2.16)
0.032 (0.81)
0.026 (0.66)
0.021 (0.53)
0.013 (0.33)
0.056 (1.42)
0.042 (1.07)
0.025 (0.63)
0.015 (0.38)
0.040 (1.01)
0.025 (0.64)
0.180 (4.57)
0.165 (4.19)
0.330 (8.38)
0.290 (7.37)
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C1879a107/95
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