BB MPY100

MPY100
®
MULTIPLIER-DIVIDER
FEATURES
APPLICATIONS
● LOW COST
● DIFFERENTIAL INPUT
● MULTIPLICATION
● DIVISION
● ACCURACY 100% TESTED AND
GUARANTEED
● NO EXTERNAL TRIMMING REQUIRED
● LOW NOISE: 90µVrms, 10Hz to 10kHz
● HIGHLY RELIABLE ONE-CHIP DESIGN
●
●
●
●
●
●
● DIP OR TO-100 TYPE PACKAGE
● WIDE TEMPERATURE OPERATION
SQUARING
SQUARE ROOT
LINEARIZATION
POWER COMPUTATION
ANALOG SIGNAL PROCESSING
ALGEBRAIC COMPUTATION
● TRUE RMS-TO-DC CONVERSION
DESCRIPTION
The MPY100 multiplier-divider is a low cost precision device designed for general purpose application.
In addition to four-quadrant multiplication, it also
performs analog square root and division without the
bother of external amplifiers or potentiometers. Lasertrimmed one-chip design offers the most in highly
reliable operation with guaranteed accuracies.
Because of the internal reference and pretrimmed
accuracies the MPY100 does not have the restrictions
of other low cost multipliers. It is available in both
TO-100 and DIP ceramic packages.
X1
V-I
X2
Multiplier Core
Y1
V-I
Out
A
Y2
Z1
V-I
Attenuator
High Gain
Output Amplifier
Z2
International Airport Industrial Park • Mailing Address: PO Box 11400
Tel: (520) 746-1111 • Twx: 910-952-1111 • Cable: BBRCORP •
©
1987 Burr-Brown Corporation
• Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd. • Tucson, AZ 85706
Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132
PDS-412D
Printed in U.S.A. March, 1995
SPECIFICATIONS
At TA = +25°C and ±VS = 15VDC, unless otherwise specified.
MPY100A
PARAMETER
CONDITIONS
MULTIPLIER PERFORMANCE
Transfer Function
MIN
MPY100B/C
TYP
MAX
(X1 – X2)(Y1 –Y2)
–10V ≤ X, Y ≤ 10V
TA = +25°C
–25°C ≤ TA ≤ +85°C
–55°C ≤ TA ≤ +125°C
±50/25
±2.0/±0.7
±0.025
*
±0.05
±7
±50
±0.3
*
±0.7
mV
mV/°C
mV/°C
mV/%
±0.05
*/*
±0.008
*
±0.08
±0.08
*/*
*/*
*
*
% FSR
% FSR
100
6
0.1
30/30
*/*
*/*
30
*
0.15
*/*
0.1
*
mVp-p
mVp-p
mVp-p/°C
mVp-p/°C
mVp-p/%
*/*
*
±1.5
±0.75/0.35
±0.35
% FSR
±4.0
±2.0/1.0
±1.0
% FSR
±5.0
±2.5/1.0
±1.0
% FSR
*/*
*
±1.2
±0.6/0.3
±0.3
% FSR
+√10(Z2 – Z1) + X2
±2
*/*
±1/0.5
*
±0.5
% FSR
550
70
5
320
20
2
0.2
*/*
*/*
*/*
*/*
*/*
*/*
*/*
*
*
*
*
*
*
*
kHz
kHz
kHz
kHz
V/µs
µs
µs
10(Z2 – Z1)
(X1 – X2)2
10
–10V ≤ X ≤ +10V
Small-Signal
Small-Signal
|VO| = 10V, RL = 2kΩ
|VO| = 10V, RL = 2kΩ
ε = ±1%, ∆VO = 20V
50% Output Overload
±10
X, Y, Z(2)
X, Y, Z
+ Y1
+ Z2
*
*/*
*
±VCC
*/*
*/*
1.5
*
*
*/*
2
*
V
mA
Ω
*
*/*
*/*
±10
±5
*
*
V
V
MΩ
µA
*/*
10
1.4
®
MPY100
% FSR
% FSR/°C
% FSR/°C
% FSR/%
% FSR
% FSR/°C
% FSR/°C
% FSR %
SQUARER PERFORMANCE
Transfer Function
OUTPUT CHARACTERISTICS
Rated Output
Voltage
IO = ±5mA
Current
VO = ±10V
Output Resistance
f = DC
±0.5
*
*/*
*/*
X = 10V
–10V ≤ Z ≤ +10V
X = 1V
–1V ≤ Z ≤ +1V
+0.2V ≤ X ≤ +10V
–10V ≤ Z ≤ +10V
INPUT CHARACTERISTICS
Input Voltage Range
Rated Operation
Absolute Maximum
Input Resistance
Input Bias Current
UNITS
±0.12
±0.008
(X1 – X2)
AC PERFORMANCE
Small-Signal Bandwidth
% Amplitude Error
% (0.57°) Vector Error
Full Power Bandwidth
Slew Rate
Settling Time
Overload Recovery
±10/7
±0.7/0.3
MAX
*/*
X1 > X2
Total Error
±100
±2.0
TYP
±0.25
X = 20Vp-p; Y = ±10VDC
Y = 20Vp-p: X = ±10VDC
f = 50Hz
X = 20Vp-p; Y = 0
Y = 20Vp-p; X = 0
–25°C ≤ TA ≤ +85°C
–55°C ≤ TA ≤ 125°C
SQUARE ROOTER PERFORMANCE
Transfer Function
Z 1 < Z2
Total Error
1V ≤ Z ≤ 10V
MIN
*/*
±50
±0.7
TA = +25°C
–25°C ≤ TA ≤ +85°C
–55°C ≤ TA ≤ +125°C
Total Error (with
external adjustments)
MAX
±1.0/0.5
±0.008/0.008 ±0.02/0.02
±0.05
TA = +25°C
–25°C ≤ TA ≤ +85°C
–55°C ≤ TA ≤ +125°C
DIVIDER PERFORMANCE
Transfer Function
±2.0
±0.05
±0.017
TYP
*/*
+ Z2
10
Total Error
Initial
vs Temperature
vs Temperature
vs Supply(1)
Individual Errors
Output Offset
Initial
vs Temperature
vs Temperature
vs Supply(1)
Scale Factor Error
Initial
vs Temperature
vs Temperature
vs Supply(1)
Nonlinearity
X Input
Y Input
Feedthrough
X Input
Y Input
vs Temperature
vs Temperature
vs Supply(1)
MIN
MPY100S
SPECIFICATIONS
(CONT)
At TA = +25°C and ±VS = 15VDC, unless otherwise specified.
MPY100A
PARAMETER
CONDITIONS
OUTPUT NOISE VOLTAGE
fO = 1Hz
fO = 1kHz
l/f Corner Frequency
fB = 5Hz to 10kHz
fB = 5Hz to 5MHz
MIN
TYP
MPY100B/C
MAX
MIN
MPY100S
TYP
MAX
MIN
TYP
MAX
UNITS
X=Y=0
6.2
0.6
110
60
1.3
POWER SUPPLY REQUIREMENTS
Rated Voltage
Operating Range
Derated Performance
Quiescent Current
TEMPERATURE RANGE (Ambient)
Specification
Operating Range
Derated Performance
Storage
±8.5
*/*
*/*
*/*
*/*
*/*
±15
*/*
±20
±5.5
*
*/*
*/*
*
*/*
–25
–55
–65
+85
+125
+150
µV/√Hz
µV/√Hz
Hz
µVrms
mVrms
*
*
*
*
*
*
VDC
VDC
mA
+125
*
*
°C
°C
°C
*
*/*
*/*
*/*
*/*
*/*
*/*
–55
*
*
* Same as MPY100A specification.
*/* B/C grades same as MPY100A specification.
NOTES: (1) Includes effects of recommended null pots. (2) Z2 input resistance is 10MΩ, typical, with VOS pin open. If VOS pin is grounded or used for optional offset
adjustment, the Z2 input resistance may be as low as 25kΩ
PIN CONFIGURATIONS
Top View
Top View
DIP
TO-100
Y2
Z1
1
14 +VCC
Out
2
13 Y1
–VCC
3
12 Y2
NC
4
11 VOS
NC
5
10 Z2
NC
6
9
X2
X1
7
8
NC
Y1
10
VOS
9
1
+VCC
2
8
Z2
Z1
3
7
X2
Out
6
4
X1
5
–VCC
NOTES: (1) VOS adjustment optional not normally recommended. VOS pin
may be left open or grounded. (2) All unused input pins should be grounded.
NOTES: (1) VOS adjustment optional not normally recommended. VOS pin
may be left open or grounded. (2) All unused input pins should be grounded.
ORDERING INFORMATION
ABSOLUTE MAXIMUM RATINGS
MODEL
MPY100AG
MPY100AM
MPY100BG
MPY100BM
MPY100CG
MPY100CM
MPY100SG
MPY100SM
Supply ........................................................................................... ±20VDC
Internal Power Dissipation(1) .......................................................... 500mW
Differential Input Voltage(2) ........................................................... ±40VDC
Input Voltage Range(2) ................................................................. ±20VDC
Storage Temperature Range ......................................... –65°C to +150°C
Operating Temperature Range .................................... –55°C to +125°C
Lead Temperature (soldering, 10s) ............................................... +300°C
Output Short-circuit Duration(3) ................................................ Continuous
Junction Temperature .................................................................... +150°C
PACKAGE
TEMPERATURE RANGE
14-Pin Ceramic DIP
Metal TO-100
14-Pin Ceramic DIP
Metal TO-100
14-Pin Ceramic DIP
Metal TO-100
14-Pin Ceramic DIP
Metal TO-100
–25°C to +85°C
–25°C to +85°C
–25°C to +85°C
–25°C to +85°C
–25°C to +85°C
–25°C to +85°C
–55°C to +125°C
–55°C to +125°C
PACKAGE INFORMATION
NOTES: (1) Package must be derated on θJC = 15°C/W and θJA =
165°C/W for the metal package and θJC = 35°C/W and θJA = 220°C/
W for the ceramic package. (2) For supply voltages less than ±20VDC,
the absolute maximum input voltage is equal to the supply voltage. (3)
Short-circuit may be to ground only. Rating applies to +85°C ambient
for the metal package and +65°C for the ceramic package.
MODEL
MPY100AG
MPY100AM
MPY100BG
MPY100BM
MPY100CG
MPY100CM
MPY100SG
MPY100SM
PACKAGE
PACKAGE DRAWING
NUMBER(1)
14-Pin Ceramic DIP
Metal TO-100
14-Pin Ceramic DIP
Metal TO-100
14-Pin Ceramic DIP
Metal TO-100
14-Pin Ceramic DIP
Metal TO-100
169
007
169
007
169
007
169
007
NOTE: (1) For detailed drawing and dimension table, please see end of data
sheet, or Appendix D of Burr-Brown IC Data Book.
®
3
MPY100
SIMPLIFIED SCHEMATIC
+VCC
A
Z2
Out
25kΩ
X1
X2
25kΩ
25kΩ
Y2
3.8kΩ
Y1
25kΩ
25kΩ
25kΩ
25kΩ
Z1
25kΩ
VOS
500µA
500µA
500µA
–VCC
CONNECTION DIAGRAM
+15VDC
+VS
X1
Z1
VO
X2
Out
Y1
Y2
VOS
–VS
Z2
(X1 – X2)(Y1 – Y2)
10
(1)
NOTE: (1) Optional component.
100kΩ
–15VDC
DICE INFORMATION
PAD
FUNCTION
1
2
3
4
5
6
7
8
9
10
Y2
VOS
Z2
X2
X1
VO
Z1
+V
–V
Y1
Substrate Bias: –VCC
MECHANICAL INFORMATION
Die Size
Die Thickness
Min. Pad Size
Backing
MPY100 DIE TOPOGRAPHY
®
MPY100
4
MILS (0.001")
MILLIMETERS
107 x 93 ±5
20 ±3
4x4
2.72 x 2.36 ±0.13
0.51 ±0.08
0.10 x 0.10
Gold
TYPICAL PERFORMANCE CURVES
At TA = +25°C and ±VS = 15VDC, unless otherwise specified.
NONLINEARITY vs FREQUENCY
100
Input Signal = 20Vp-p
10
Nonlinearity (% of FSR)
Magnitude of Total Output Error (% of FSR)
TOTAL ERROR vs AMBIENT TEMPERATURE
10
1
1
X
0.1
Y
0.01
0.001
0.1
–100
–50
0
100
50
10
150
100
1k
100k
10k
FEEDTHROUGH vs FREQUENCY
OUTPUT AMPLITUDE vs FREQUENCY
5
1000
Small Signal
500
Feedthrough Voltage (mVp-p)
1M
Frequency (Hz)
Ambient Temperature (°C)
Output Amplitude (dB)
Input Signal = 20Vp-p
200
100
X Feedthrough
50
20
0
–5
X
–10
Y
–15
10
Y Feedthrough
–20
5
10
100
1k
10k
100k
1M
10k
10M
100k
Frequency (Hz)
LARGE SIGNAL RESPONSE
10M
INPUT VOLTAGE FOR LINEAR RESPONSE
10
20
Input
Output
16
5
0
RL = 2kΩ
CL = 150pF
–5
Positive Common-Mode
Differential
Negative Common-Mode
18
Input Range (V)
Output Voltage (V)
1M
Frequency (Hz)
14
12
10
8
6
4
2
0
–10
0
1
3
2
4
5
0
2
4
6
8
10
12
14
16
18
20
Power Supply Voltage (±VCC)
Time (µs)
®
5
MPY100
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C and ±VS = 15VDC, unless otherwise specified.
OUTPUT VOLTAGE vs OUTPUT CURRENT
COMMON-MODE REJECTION vs FREQUENCY
80
25
Output Voltage (±V)
X = 12Vp-p
Y = ±10VDC
60
50
40
20
VCC = ±20V
15
VCC = ±15V
VCC = ±10V
10
VCC = ±8.5V
5
30
0
20
10
100
1k
10k
100k
1M
10M
0
2
4
Frequency (Hz)
SUPPLY CURRENT vs AMBIENT TEMPERATURE
14
12
5mA Load
10
8
6
Quiescent
4
2
0
–100
–50
0
50
Ambient Temperature (°C)
®
MPY100
6
8
10
Output Current (±mA)
16
Supply Current (mA)
CMR (dB)
+25°C
–55°C
Y = 12Vp-p
X = ±10VDC
70
6
100
150
12
14
16
THEORY OF OPERATION
and is modulated by the voltage, V2, to give
The MPY100 is a variable transconductance multiplier consisting of three differential voltage-to-current converters, a
multiplier core and an output differential amplifier as illustrated in Figure 1.
Substituting this into the original equation yields the overall
transfer function
The basic principle of the transconductance multiplier can
be demonstrated by the differential stage in Figure 2.
which shows the output voltage to be the product of the two
input voltages, V1 and V2.
For small values of the input voltage, V1, that are much
smaller than VT, the transistor’s thermal voltage, the differential output voltage, VO, is:
Variations in IE due to V2 cause a large common-mode
voltage swing in the circuit. The errors associated with this
common-mode voltage can be eliminated by using two
differential stages in parallel and cross-coupling their outputs as shown in Figure 3.
gm ≈ V2/VTRE
VO = gmRLV1 = V1V2 (RL/VTRE)
VO = gm RLV1
The transconductance gm of the stage is given by:
gm = IE/VT
+VS
RL
Stable
Reference
and Bias
RL
+
+VS
VO = A
(X1 – X2)(Y1 – Y2)
10
X1
V-I
–
VO
–VS
I1
– (Z1 – Z2)
Q1
+
Transfer Function
I2
I3
Q2
I4
Q3
Q4
V1
X2
Multiplier
Core
–
Y1
Q5
V-I
RE
Out
RE
Q6
A
Y2
+
V2
High Gain
Output Amplifier
Z1
V-I
–
Attenuator
IT
Z2
–VCC
FIGURE 1. MPY100 Functional Block Diagram.
FIGURE 3. Cross-Coupled Differential Stages as a VariableTransconductance Multiplier.
An analysis of the circuit in Figure 3 shows it to have the
same overall transfer function as before:
+VCC
I1
RL
RL
I2
VO = V1V2 (RL/VTRE).
For input voltages larger than VT, the voltage-to-current
transfer characteristics of the differential pair Q1, Q2 or Q3
and Q4 are no longer linear. Instead, their collector currents
are related to the applied voltage V1
– VO +
Q1
+
Q2
V1
–
I1
Q3
+
RE
I2
IE
=
I3
I4
V1
=e
VT
The resultant nonlinearity can be overcome by developing
V1 logarithmically to exactly cancel the exponential relationship just derived. This is done by diodes D1 and D2 in
Figure 4.
V2
–
The emitter degeneration resistors, RX and RY, in Figure 4,
provide a linear conversion of the input voltages to differential current, IX and IY, where:
FIGURE 2. Basic Differential Stage as a Transconductance
Multiplier.
®
7
MPY100
IX = VX/RX and IY = VY/RY
CAPACITIVE LOADS
Analysis of Figure 4 shows the voltage VA to be:
VA = (2RL/I1)(IXIY)
Stable operation is maintained with capacitive loads to
1000pF in all modes, except the square root mode for which
50pF is a safe upper limit. Higher capacitive loads can be
driven if a 100Ω resistor is connected in series with the
MPY100’s output.
Since IX and IY are linearly related to the input voltages VX
and VY, VA may also be written:
VA = KVXVY
where K is a scale factor. In the MPY100, K is chosen to be
0.1.
DEFINITIONS
The addition of the Z input alters the voltage VA to:
VA = KVXVY – VZ
TOTAL ERROR (Accuracy)
Total error is the actual departure of the multiplier output
voltage form the ideal product of its input voltages. It
includes the sum of the effects of input and output DC
offsets, gain error and nonlinearity.
Therefore, the output of the MPY100 is:
VO = A[KVXVY – VZ]
where A is the open-loop gain of the output amplifier.
Writing this last equation in terms of the separate inputs to
the MPY100 gives
VO = A
(X1 – X2)(Y1 – Y2)
10
OUTPUT OFFSET
Output offset is the output voltage when both inputs VX and
VY are 0V.
– (Z1 – Z2)
SCALE FACTOR ERROR
the transfer function of the MPY100.
Scale factor error is the difference between the actual scale
factor and the ideal scale factor.
WIRING PRECAUTIONS
In order to prevent frequency instability due to lead inductance of the power supply lines, each power supply should
be bypassed. This should be done by connecting a 10µF
tantalum capacitor in parallel with a 1000pF ceramic capacitor from the +VCC and –VCC pins of the MPY100 to the
power supply common. The connection of these capacitors
should be as close to the MPY100 as practical.
NONLINEARITY
Nonlinearity is the maximum deviation from a best
straightline (curve fitting on input-output graph) expressed
as a percent of peak-to-peak full scale output.
FEEDTHROUGH
Feedthrough is the signal at the output for any value of VX
or VY within the rated range, when the other input is zero.
+VCC
RCM
RL
RL
I4
D1
D2
I1
I2 I3
+
VA
–
VO
A
+
V1
–
X1
Q7
Q1
Q8
Q2
Q3
Q5
Q4
Q6
Z1
Q10
+
RX
2
RX
2
RY
2
RY
2
–
+
VY
RZ
2
RZ
2
–
211
211
–VCC
FIGURE 4. MPY100 Simplified Circuit Diagram.
®
8
VZ
–
Y2
X2
MPY100
Q9
Y1
+
VX
Out
Z2
211
εDIVIDER = 10 εMULTIPLIER/(X1 – X2)
SMALL SIGNAL BANDWIDTH
It is obvious from this error equation that divider error
becomes excessively large for small values of X1 – X2. A 10to-1 denominator range is usually the practical limit. If more
accurate division is required over a wide range of denominator voltages, an externally generated voltage may be
Small signal bandwidth is the frequency at which the output
is down 3dB from its low-frequency value for nominal
output amplitude of 10% of full scale.
1% AMPLITUDE ERROR
The 1% amplitude error is the frequency the output amplitude is in error by 1%, measured with an output amplitude
of 10% of full scale.
(X1 – X2)(Y1 – Y2)
VO =
VX, ±10V,
FS
1% VECTOR ERROR
The 1% vector error is the frequency at which a phase error
of 0.01 radians (0.57°) occurs. This is the most sensitive
measure of dynamic error of a multiplier.
X1
10
+ Z2
Z1
VO, ±10V, FS
X2
MPY100
Out
Y1
VY, ±10V,
FS
Y2
VOS
–VCC
+VCC
Optional
Summing
Input, ±10V, FS
Z2
(1)
TYPICAL APPLICATIONS
NOTE: (1) Optional balance
potentiometer.
100kΩ
MULTIPLICATION
–15VDC
Figure 5 shows the basic connection for four-quadrant multiplication.
+15VDC
FIGURE 5. Multiplier Connection.
The MPY100 meets all of its specifications without trimming. Accuracy can, however be improved over a limited
range by nulling the output offset voltage using the 100Ω
optional balance potentiometer shown in Figure 5.
+VCC
50kΩ
470kΩ
To the appropriate
input terminal.
AC feedthrough may be reduced to a minimum by applying
an external voltage to the X or Y input as shown in Figure
6.
1kΩ
–VCC
Z2, the optional summing input, may be used to sum a
voltage into the output of the MPY100. If not used, this
terminal, as well as the X and Y input terminals, should be
grounded. All inputs should be referenced to power supply
common.
FIGURE 6. Optional Trimming Configuration.
R2
10kΩ
Figure 7 shows how to achieve a scale factor larger than the
nominal 1/10. In this case, the scale factor is unity which
makes the transfer function
X1
MPY100
VO = KVXVY = K(X1 – X2)(Y1 – Y2).K =
R1
90kΩ
Z1
X2
VO
Out
Y1
1 + (R1/R2)
Z2
Y2
10
0.1 ≤ K ≤ 1
This circuit has the disadvantage of increasing the output
offset voltage by a factor of 10, which may require the use
of the optional balance control as in Figure 1 for some
applications. In addition, this connection reduces the small
signal bandwidth to about 50kHz.
FIGURE 7. Connection for Unity Scale Factor.
VO =
VXDemonimator
±0.2V to +10V, FS
DIVISION
Figure 8 shows the basic connection for two-quadrant
division. This configuration is a multiplier-inverted analog
divider, i.e., a multiplier connected in the feedback loop of
an operational amplifier. In the case of the MPY100, this
operational amplifier is the output amplifier shown in
Figure 1.
X1
(X1 – X2)
Z1
+ Y1
VO = ±10V, FS
X2
MPY100
Optional Summing
Input, ±10V, FS
10(Z2 – Z1)
Out
Y1
Z2
Y2
V2
Numerator
±10V, FS
The divider error with a multiplier-inverted analog divider is
approximately:
FIGURE 8. Divider Connection.
®
9
MPY100
MORE CIRCUITS
The theory and procedures for developing virtually any
function generator or linearization circuit can be found in the
Burr-Brown/McGraw Hill book “FUNCTION CIRCUITS Design and Applications.”
applied to the unused X-input (see Optional Trim Configuration). To trim, apply a ramp of +100mV to +1V at 100Hz
to both X1 and Z1 if X2 is used for offset adjustment,
otherwise reverse the signal polarity and adjust the trim
voltage to minimize the variation in the output. An alternative to this procedure would be to use the Burr-Brown
DIV100, a precision log-antilog divider.
VO = + 10(Z2 – Z1) +X2
SQUARING
VO =
(X1 – X2)2
10
Optional
Summing
Input,
±10V, FS
+ Z2
X1
Z1
VO
X2
MPY100
Out
Y1
X1
Z1
X2
MPY100
VZ
Out
Y1
VX
±10V, FS
+0.2V ≤ (Z2 – Z1) ≤ +10V
(a) Circuit for positive VZ.
Z2
Y2
RL
Z2
Y2
VO = ±10V, FS
Optional
Summing
Input, ±10V, FS
Optional
Summing
Input,
±10V, FS
FIGURE 9. Squarer Connection.
VO = – 10(Z2 – Z1) +X2
X1
Z1
VO
X2
MPY100
SQUARE ROOT
Y1
Figure 10 shows the connection for taking the square root of
the voltage VZ. The diode prevents a latching condition
which could occur if the input momentarily changed polarity. This latching condition is not a design flaw in the
MPY100, but occurs when a multiplier is connected in the
feedback loop of an operational amplifier to perform square
root functions.
Y2
Out
RL
Z2
VZ
+0.2V ≤ (Z2 – Z1) ≤ +10V
(b) Circuit for negative VZ.
FIGURE 10. Square Root Connection.
The load resistance, R L, must be in the range of
10kΩ ≤ RL ≤ 1MΩ. This resistance must be in the circuit as
it provides the current necessary to operate the diode.
VO =
(V2 – V1)
V1
100
1% per volt
V1
PERCENTAGE COMPUTATION
+0.2V ≤ V1 ≤ +10V
The circuit of Figure 11 has a sensitivity of 1V/% and is
capable of measuring 10% deviations. Wider deviation can
be measured by decreasing the ratio of R2/R1.
X1
Z1
X2
MPY100
Y1
Y2
BRIDGE LINEARIZATION
Z2
9kΩ
V2
1kΩ
The use of the MPY100 to linearize the output from a bridge
circuit makes the output VO independent of the bridge
supply voltage. See Figure 12.
FIGURE 11. Percentage Computation.
TRUE RMS-TO-DC CONVERSION
The rms-to-DC conversion circuit of Figure 13 gives greater
accuracy and bandwidth but with less dynamic range than
most rms-to-DC converters.
SINE FUNCTION GENERATOR
The circuit in Figure 14 uses implicit feedback to implement
the following sine function approximation:
VO = (1.5715V1 – 0.004317V13)/(1 + 0.001398V12)
= 10 sin (9V1)
®
MPY100
VO
Out
10
RG
40kΩ
V
R + ∆R
R
Z1
X1
V1 INA101
MPY100
Y2
V1 =
V
2
1
2R
1+
∆R
V2 = V
VO
Out
Y1
G=2
R
R
Z1
X2
V2
1
2R
1+
∆R
VO = 5
R1
Z2
R2
R1 + R2 ∆R
R
R2
NOTE: V should be as large as possible to minimize divider errors. But V ≤ [10 + (20R/∆R)]
to keep V2 within the input voltage limits of the MPY100.
FIGURE 12. Bridge Linearization.
Matched to 0.025%
R1
10kΩ
20kΩ
R2
10kΩ
OPA111
VIN
(±5V pk)
10µF
X1
Z1
10kΩ
X2
DC
MPY100
Out
C2
10µF
Y1
AC
10kΩ
Y2
Z2
VO
VO = VIN2
0 to 5V
Mode Switch
OPA111
+VS
10MΩ
50kΩ
Zero
Adjust
–VS
10kΩ
20kΩ
FIGURE 13. True RMS-to-DC Conversion.
®
11
MPY100
23.165kΩ
71.548kΩ
X1
10kΩ
Z1
X2
MPY100
VO = 10 sin 9V1
Out
Y1
Y2
V1
X1
Z2
5.715kΩ
Z1
X2
MPY100
10kΩ
Out
Y1
Z2
Y2
(–10V ≤ V1 ≤ +10V, and 1V = 9°)
FIGURE 14. Sine Function Generator
IL
ei(t) = 2 Eirms Sin ωt
iL(t) = 2 ILrms Sin (ωt + θ )
ei
R4
Load
∝ei
R1
R2
R5
∝ =R5/(R4 +R5)
γ =(–R1R3)/R2
X
XY
R3
10
γiL
Instantaneous
Power
Y
Real Power
(∝γ/10)(EirmsILrms cosθ )
FIGURE 15. Single-Phase Instantaneous and Real Power
Measurement.
The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN
assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject
to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not
authorize or warrant any BURR-BROWN product for use in life support devices and/or systems.
®
MPY100
12