FEATURES
4-Quadrant Multiplication
Low Cost 8-Lead Package
Complete—No External Components Required
Laser-Trimmed Accuracy and Stability
Total Error within 2% of FS
Differential High Impedance X and Y Inputs
High Impedance Unity-Gain Summing Input
Laser-Trimmed 10 V Scaling Reference
APPLICATIONS
Multiplication, Division, Squaring
Modulation/Demodulation, Phase Detection
Voltage Controlled Amplifiers/Attenuators/Filters
PRODUCT DESCRIPTION
The AD633 is a functionally complete, four-quadrant, analog
multiplier. It includes high impedance, differential X and Y
inputs and a high impedance summing input (Z). The low
impedance output voltage is a nominal 10 V full scale provided
by a buried Zener. The AD633 is the first product to offer these
features in modestly priced 8-lead plastic DIP and SOIC packages.
The AD633 is laser calibrated to a guaranteed total accuracy of
2% of full scale. Nonlinearity for the Y input is typically less
than 0.1% and noise referred to the output is typically less than
100 µV rms in a 10 Hz to 10 kHz bandwidth. A 1 MHz bandwidth, 20 V/µs slew rate, and the ability to drive capacitive loads
make the AD633 useful in a wide variety of applications where
simplicity and cost are key concerns.
The AD633’s versatility is not compromised by its simplicity.
The Z-input provides access to the output buffer amplifier,
enabling the user to sum the outputs of two or more multipliers,
increase the multiplier gain, convert the output voltage to a
current, and configure a variety of applications.
The AD633 is available in an 8-lead plastic DIP package (N)
and 8-lead SOIC (R). It is specified to operate over the 0°C to
70°C commercial temperature range (J Grade) or the –40°C to
+85°C industrial temperature range (A Grade).
Analog Multiplier
AD633
CONNECTION DIAGRAMS
8-Lead Plastic DIP (N) Package
+V
1
X1
X2
Y1
Y2
1
2
1
10V
3
1
4
AD633JN/AD633AN
A
8-Lead Plastic SOIC (RN-8) Package
Y1
1
1
1
2
Y2
–V
10V
3
S
4
Z
AD633JR/AD633AR
W =
(X
– X2) (Y1 – Y2)
1
10V
A
PRODUCT HIGHLIGHTS
1. The AD633 is a complete four-quadrant multiplier offered in
low cost 8-lead plastic packages. The result is a product that
is cost effective and easy to apply.
2. No external components or expensive user calibration are
required to apply the AD633.
3. Monolithic construction and laser calibration make the
device stable and reliable.
4. High (10 MΩ) input resistances make signal source loading
negligible.
5. Power supply voltages can range from ±8 V to ±18 V. The
internal scaling voltage is generated by a stable Zener diode;
multiplier accuracy is essentially supply insensitive.
8
S
W
7
Z
6
–V
5
S
X2
8
1
X1
7
+V
6
S
W
5
+ Z
REV. E
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.
Scale Voltage ErrorSF = 10.00 V Nominal±0.25%% Full Scale
Supply RejectionV
Nonlinearity, XX = ±10 V, Y = +10 V± 0.4
Nonlinearity, YY = ±10 V, X = +10 V±0.1
X FeedthroughY Nulled, X = ±10 V±0.3
Y FeedthroughX Nulled, Y = ± 10 V±0.1
Output Offset Voltage±5
Bias Current X, Y, Z0.82.0µA
Differential Resistance10MΩ
POWER SUPPLY
Supply Voltage
Rated Performance±15V
Operating Range
ⴞ
8
ⴞ
18V
Supply CurrentQuiescent46mA
Specifications shown in boldface are tested on all production units at electrical test. Results from those tests are used to calculate outgoing quality levels. All min and
max specifications are guaranteed, although only those shown in boldface are tested on all production units.
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.
For supply voltages less than ± 18 V, the absolute maximum input voltage is equal to
the supply voltage.
–2–
ORDERING GUIDE
TemperaturePackagePackage
ModelRangeDescriptionOption
AD633AN–40°C to +85°C Plastic DIPN-8
AD633AR–40°C to +85°C Plastic SOICRN-8
AD633AR-REEL–40°C to +85°C 13" Tape and Reel RN-8
AD633AR-REEL7 –40°C to +85°C 7" Tape and ReelRN-8
AD633JN0°C to 70°CPlastic DIPN-8
AD633JR0°C to 70°CPlastic SOICRN-8
AD633JR-REEL0°C to 70°C13" Tape and Reel RN-8
AD633JR-REEL70°C to 70°C7" Tape and ReelRN-8
REV. E
Page 3
Typical Performance Characteristics–
FREQUENCY – Hz
CMRR – dB
20
100
1k10k
100k1M
TYPICAL
FOR X,Y
INPUTS
30
40
50
60
70
80
90
100
0dB = 0.1V rms, RL = 2k⍀
0
CL = 1000pF
AD633
–10
–20
OUTPUT RESPONSE – dB
–30
10k1M10M
CL = 0dB
100k
FREQUENCY – Hz
NORMAL
CONNECTION
TPC 1. Frequency Response
700
600
500
400
BIAS CURRENT – nA
300
TPC 4. CMRR vs. Frequency
1.5
1
0.5
NOISE SPECTRAL DENSITY – V/ Hz
200
–40 –20020406080 100 120 140–60
TEMPERATURE – ⴗC
TPC 2. Input Bias Current vs. Temperature (X, Y, or
Z Inputs)
14
12
OUTPUT, RL 2k⍀
10
ALL INPUTS
8
6
PEAK POSITIVE OR NEGATIVE SIGNAL – V
4
8
10
TPC 3. Input and Output Signal Ranges vs. Supply
Voltages
PEAK POSITIVE OR NEGATIVE SUPPLY – V
12141618
20
0
10
100
1k10k
FREQUENCY – Hz
TPC 5. Noise Spectral Density vs. Frequency
1000
Y-FEEDTHROUGH
100
10
P-P FEEDTHROUGH – mV
1
0
10100
1k
10k
FREQUENCY – Hz
X-FEEDTHROUGH
100k1M10M
TPC 6. AC Feedthrough vs. Frequency
100k
REV. E
–3–
Page 4
AD633
FUNCTIONAL DESCRIPTION
The AD633 is a low cost multiplier comprising a translinear
core, a buried Zener reference, and a unity gain connected
output amplifier with an accessible summing node. Figure 1
shows the functional block diagram. The differential X and Y
inputs are converted to differential currents by voltage-to-current
converters. The product of these currents is generated by the
multiplying core. A buried Zener reference provides an overall
scale factor of 10 V. The sum of (X × Y)/10 + Z is then applied
to the output amplifier. The amplifier summing node Z allows
the user to add two or more multiplier outputs, convert the
output voltage to a current, and configure various analog computational functions.
Inspection of the block diagram shows the overall transfer function to be:
XXYY
W
−
(
1212
10
−
)
(
V
)
Z=
+
(1)
ERROR SOURCES
Multiplier errors consist primarily of input and output offsets,
scale factor error, and nonlinearity in the multiplying core. The
input and output offsets can be eliminated by using the optional
trim of Figure 2. This scheme reduces the net error to scale factor
errors (gain error) and an irreducible nonlinearity component in
the multiplying core. The X and Y nonlinearities are typically
0.4% and 0.1% of full scale, respectively. Scale factor error is
typically 0.25% of full scale. The high impedance Z input should
always be referenced to the ground point of the driven system,
particularly if this is remote. Likewise, the differential X and Y
inputs should be referenced to their respective grounds to realize
the full accuracy of the AD633.
+V
S
50k⍀
300k⍀
1k⍀
–V
S
ⴞ50mV
TO APPROPRIATE
INPUT TERMINAL
(e.g., X
, X2, Z)
2
Figure 2. Optional Offset Trim Configuration
APPLICATIONS
The AD633 is well suited for such applications as modulation
and demodulation, automatic gain control, power measurement,
voltage controlled amplifiers, and frequency doublers. Note that
these applications show the pin connections for the AD633JN
pinout (8-lead DIP), which differs from the AD633JR pinout
(8-lead SOIC).
Multiplier Connections
Figure 3 shows the basic connections for multiplication. The X
and Y inputs will normally have their negative nodes grounded,
but they are fully differential, and in many applications the
grounded inputs may be reversed (to facilitate interfacing with
signals of a particular polarity while achieving some desired
output polarity) or both may be driven.
+15V
0.1F
8
S
W
7
OPTIONAL SUMMING
6
Z
S
INPUT, Z
5
0.1F
–15V
W =
– X2) (Y1 – Y2)
(X
1
10V
+ Z
X
INPUT
Y
INPUT
1
X1
2
X2
AD633JN
3
Y1
4
Y2
+V
–V
Figure 3. Basic Multiplier Connections
Squaring and Frequency Doubling
As Figure 4 shows, squaring of an input signal, E, is achieved
simply by connecting the X and Y inputs in parallel to produce
an output of E
2
/10 V. The input may have either polarity, but
the output will be positive. However, the output polarity may be
reversed by interchanging the X or Y inputs. The Z input may
be used to add a further signal to the output.
+15V
X1
X2
AD633JN
Y1
Y2
+V
–V
E
1
2
3
4
0.1F
8
S
W
7
6
Z
5
S
0.1F
–15V
W =
E
10V
2
Figure 4. Connections for Squaring
When the input is a sine wave E sin ωt, this squarer behaves as a
frequency doubler, since
2
Et
sin
()
V
1020
2
E
=−
12
()
V
cosωω
t
(2)
Equation 2 shows a dc term at the output that will vary strongly
with the amplitude of the input, E. This can be avoided using
the connections shown in Figure 5, where an RC network is
used to generate two signals whose product has no dc term. It
uses the identity:
–4–
cos sinsinθθθ=
1
2
()
2
(3)
REV. E
Page 5
+15V
0.1F
+15V
E
8
7
6
5
1
2
3
4
AD633JN
0.1F
X1
X2
Y1
Y2
–V
S
+V
S
W
Z
–15V
W' = –10V
E
E
X
0.1F
0.1F
R
10k⍀
R
10k⍀
+15V
–15V
E
X
AD711
X1
X2
AD633JN
Y1
Y2
+V
–V
E
1
R
2
3
C
4
0.1F
8
S
W
7
R1
1k⍀
6
Z
5
S
0.1F
–15V
R2
3k⍀
W =
E
10V
2
Figure 5. ”Bounceless” Frequency Doubler
At ωo = 1/CR, the X input leads the input signal by 45° (and is
attenuated by √2), and the Y input lags the X input by 45° (and
is also attenuated by √2). Since the X and Y inputs are 90° out of
phase, the response of the circuit will be (satisfying Equation 3):
W
=
10
V
()
2
E
=
40
V
()
E
2
sin
()
t
sinsin
ωω
()
oo
2
t
ω
o
45
+°
E
()
2
45
t
−°
(4)
1
which has no dc component. Resistors R1 and R2 are included to
restore the output amplitude to 10 V for an input amplitude of 10 V.
The amplitude of the output is only a weak function of frequency:
the output amplitude will be 0.5% too low at ω = 0.9 ω
ω
= 1.1 ωo.
o
, and
o
Generating Inverse Functions
Inverse functions of multiplication, such as division and square
rooting, can be implemented by placing a multiplier in the feedback loop of an op amp. Figure 6 shows how to implement a
square rooter with the transfer function
WEV=
10
()
(5)
for the condition E < 0.
+15V
+15V
0.1F
7
4
1N4148
0.1F
OP27
E
–15V
1
2
3
4
1N4148
X1
X2
AD633JN
Y1
Y2
+V
–V
0.1F
8
S
W
7
6
Z
0.1F
5
S
–15V
10E
W =
()
V
Figure 6. Connections for Square Rooting
AD633
Figure 7. Connections for Division
Likewise, Figure 7 shows how to implement a divider using a
multiplier in a feedback loop. The transfer function for the
divider is
WV
' =−
1
X
INPUT
2
3
Y
INPUT
4
Figure 8. Connections for Variable Scale Factor
Variable Scale Factor
In some instances, it may be desirable to use a scaling voltage
other than 10 V. The connections shown in Figure 8 increase
the gain of the system by the ratio (R1 + R2)/R1. This ratio is
limited to 100 in practical applications. The summing input, S,
may be used to add an additional signal to the output or it may
be grounded.
Current Output
The AD633’s voltage output can be converted to a current
output by the addition of a resistor R between the AD633’s W
and Z pins as shown in Figure 9. This arrangement forms
X
INPUT
Y
INPUT
E
10
()
E
X
+15V
X1
X2
AD633JN
Y1
Y2
1
X1
2
X2
3
Y1
4
Y2
+V
–V
AD633JN
0.1F
8
S
W
7
6
Z
5
S
0.1F
+V
S
W
Z
–V
S
–15V
+15V
8
7
6
5
(6)
– X2) (Y1 – Y2)
(X
1
W =
R1
R2
S
0.1F
R
0.1F
10V
1k⍀ R1, R2 100k⍀
(X1 – X2) (Y1 – Y2)
1
IO =
R
1k⍀ R 100k⍀
10V
(R1 + R2)
R1
+ S
–15V
REV. E
–5–
Figure 9. Current Output Connections
Page 6
AD633
the basis of voltage controlled integrators and oscillators as will
be shown later in this Applications section. The transfer function of this circuit has the form
XXYY
−
(
1212
1
I
=
O
R
10
−
)
(
V
)
(7)
Linear Amplitude Modulator
The AD633 can be used as a linear amplitude modulator with
no external components. Figure 10 shows the circuit. The carrier and modulation inputs to the AD633 are multiplied to
produce a double-sideband signal. The carrier signal is fed
forward to the AD633’s Z input where it is summed with the
double-sideband signal to produce a double-sideband with carrier output.
Voltage Controlled Low-Pass and High-Pass Filters
Figure 11 shows a single multiplier used to build a voltage controlled low-pass filter. The voltage at output A is a result of
filtering, E
trol input. The break frequency, f
. The break frequency is modulated by EC, the con-
S
E
20
VRC
(
)
C
π
f
=
2
, equals
2
(8)
and the rolloff is 6 dB per octave. This output, which is at a
high impedance point, may need to be buffered.
The voltage at output B, the direct output of the AD633, has
same response up to frequency f
, the natural breakpoint of RC
1
filter,
1
INPUT
ⴞE
INPUT
sin t
C
2=π
M
1
RC
1
X1
2
X2
AD633JN
3
Y1
4
Y2
(9)
= EC/10.
1/f2
+15V
+V
–V
0.1F
8
S
W
7
6
Z
5
S
0.1F
–15V
W = 1+
E
10V
M
ECsin t
f
then levels off to a constant attenuation of f
MODULATION
CARRIER
E
Figure 10. Linear Amplitude Modulator
For example, if R = 8 kΩ and C = 0.002 µF, then output A has
a pole at frequencies from 100 Hz to 10 kHz for E
ranging
C
from 100 mV to 10 V. Output B has an additional zero at 10 kHz
(and can be loaded because it is the multiplier’s low impedance
output). The circuit can be changed to a high-pass filter Z interchanging the resistor and capacitor as shown in Figure 12.
dB
CONTROL
INPUT E
SIGNAL
INPUT E
f2 f1
+15V
X1
X2
AD633JN
Y1
Y2
+V
–V
1
C
2
3
S
4
0.1F
8
S
W
7
6
Z
5
S
0.1F
–15V
0
–6dB/OCTAVE
OUTPUTA
OUTPUT B =
R
OUTPUT A =
C
T
T2 ==
== RC
1
OUTPUTB
1 + T
1 + T2P
1 + T2P
1
W
1
1
W
2
f
P
1
1
10
E
CRC
Figure 11. Voltage Controlled Low-Pass Filter
dB
f2f1
f
OUTPUTB
+6dB/OCTAVE
OUTPUT B
C
OUTPUT A
R
CONTROL
INPUT E
SIGNAL
INPUT E
+15V
+V
1
X1
C
2
X2
AD633JN
3
S
Y1
4
Y2
8
S
W
7
6
Z
5
–V
S
–15V
0
0.1F
OUTPUTA
0.1F
Figure 12. Voltage Controlled High-Pass Filter
Voltage Controlled Quadrature Oscillator
Figure 13 shows two multipliers being used to form integrators
with controllable time constants in second order differential
equation feedback loop. R2 and R5 provide controlled current
output operation. The currents are integrated in capacitors C1
and C2, and the resulting voltages at high impedance are applied to
the X inputs of the “next” AD633. The frequency control input,
, connected to the Y inputs, varies the integrator gains with a
E
C
calibration of 100 Hz/V. The accuracy is limited by the Y input
offsets. The practical tuning range of this circuit is 100:1. C2
(proportional to C1 and C3), R3, and R4 provide regenerative
feedback to start and maintain oscillation. The diode bridge, D1
through D4 (1N914s), and Zener diode D5 provide economical
temperature stabilization and amplitude stabilization at ±8.5 V
by degenerative damping. The out-put from the second
integrator (10 V sin ωt) has the lowest distortion.
AGC AMPLIFIERS
Figure 14 shows an AGC circuit that uses an rms-to-dc converter to measure the amplitude of the output waveform. The
AD633 and A1, 1/2 of an AD712 dual op amp, form a voltage
controlled amplifier. The rms-to-dc converter, an AD736, measures the rms value of the output signal. Its output drives A2,
an integrator/comparator whose output controls the gain of the
voltage controlled amplifier. The 1N4148 diode prevents the
output of A2 from going negative. R8, a 50 kΩ variable resistor,
sets the circuit’s output level. Feedback around the loop forces
the voltages at the inverting and noninverting inputs of A2 to be
equal, thus the AGC.
–6–
REV. E
Page 7
R1
1k⍀
EC
1N914
D2
1N914
D5
1N5236
D1
D3
1N914
+15V
+V
–V
0.1F
8
S
W
7
6
Z
5
S
0.1F
R2
16k⍀
0.1F
1
X1
2
X2
AD633JN
3
Y1
4
Y2
+15V
+V
8
S
W
7
6
Z
5
–V
S
1
X1
2
X2
AD633JN
3
Y1
4
Y2
D4
1N914
–15V
–15V
Figure 13. Voltage Controlled Quadrature Oscillator
0.1F
0.1F
R3
330k⍀
C2
0.01F
R5
16k⍀
C3
0.1F
(10V) cos t
R4
16k⍀
(10V) sin t
E
C
f =
10V
AD633
kHz
E
R9
10k⍀
1N4148
1
X1
2
X2
AD633JN
3
Y1
4
Y2
C3
0.2F
0.1F
R2
1k⍀
AGC THRESHOLD
ADJUSTMENT
+15V
+V
8
S
W
7
6
Z
5
–V
S
–15V
C2
0.02F
R10
10k⍀
A2
1/2
AD712
10k⍀
0.1F
0.1F
R4
R3
10k⍀
+15V
0.1F
C1
1/2
AD712
1F
A1
COMMON
C
0.1F
1
C
V
2
IN
AD736
3
C
F
45
–V
S
+V
OUTPUT
C
8
7
S
6
AV
–15V
C4
33F
+15V
OUTPUT
R8
LEVEL
50k⍀
ADJUST
–15V
Figure 14. Connections for Use in Automatic Gain Control Circuit
R5
10k⍀
R6
1k⍀
+15V
E
OUT
0.1F
REV. E
–7–
Page 8
AD633
OUTLINE DIMENSIONS
8-Lead Plastic Dual-in-Line Package [PDIP]
(N-8)
Dimensions shown in inches and (millimeters)
0.375 (9.53)
0.365 (9.27)
0.355 (9.02)
8
1
0.100 (2.54)
0.180
(4.57)
MAX
0.150 (3.81)
0.130 (3.30)
0.110 (2.79)
0.022 (0.56)
0.018 (0.46)
0.014 (0.36)
CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
COMPLIANT TO JEDEC STANDARDS MO-095AA
BSC
5
4
0.295 (7.49)
0.285 (7.24)
0.275 (6.98)
0.015
(0.38)
MIN
SEATING
PLANE
0.060 (1.52)
0.050 (1.27)
0.045 (1.14)
0.325 (8.26)
0.310 (7.87)
0.300 (7.62)
0.150 (3.81)
0.135 (3.43)
0.120 (3.05)
0.015 (0.38)
0.010 (0.25)
0.008 (0.20)
C00786–0–10/02(E)
8-Lead Standard Small Outline Package [SOIC]
Narrow Body
(RN-8)
Dimensions shown in millimeters and (inches)
5.00 (0.1968)
4.80 (0.1890)
4.00 (0.1574)
3.80 (0.1497)
0.25 (0.0098)
0.10 (0.0040)
COPLANARITY
0.10
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN