icl8013 Intersil Corporation, icl8013 Datasheet - Page 7

• Manufacturer Part Number: icl8013
• Description: 1mhz, Four Quadrant Analog Multiplier
• Manufacturer: Intersil Corporation

Squaring
The squaring function is achieved by simply multiplying with
the two inputs tied together. The squaring circuit may also be
used as the basis for a frequency doubler since cos
(cos 2ωt + 1).
Square Root
Tying the X and Y inputs together and using overall
feedback from the op amp results in the square root function.
X
7.5kΩ
X
Y
X
Y
IN
IN
IN
IN
X
Z
IN
IN
FIGURE 9B. SQUARER CIRCUIT CONNECTION
FIGURE 8B. DIVISION CIRCUIT CONNECTION
FACTOR
ADJUST
SCALE
(0 TO -10V)
FIGURE 9A. SQUARER BLOCK DIAGRAM
5kΩ
MODULATOR
FIGURE 8A. DIVISION BLOCK DIAGRAM
Y
IN
X
IN
6
3
1
X
7
3
6
1
OS
I
O
X
7
10
ICL8013
= X
OS
Y
OS
IN
10
I
ICL8013
O
Y
• Y
OS
Z
9
7
Z
I
OS
Z
IN
Z
IN
IN
Z
9
OS
GAIN
R =
R =
OUTPUT =
OP AMP
10
OP AMP
1
10
4
1
4
5K
7.5K
V
OUT
OUTPUT =
10Z
X
IN
V
=
IN
OUT
10Z
2
X
ωt =
IN
IN
=
X
10
X
IN
1
10
IN
2
/
2
2
ICL8013
The output of the modulator is again forced to equal the
current produced by the Z input.
The output is a negative voltage which maintains overall
negative feedback. A diode in series with the op amp output
prevents the latchup that would otherwise occur for negative
input voltages.
SQUARE ROOT TRIMMING PROCEDURE
Variable Gain Amplifier
Most applications for the ICL8013 are straight forward
variations of the simple arithmetic functions described
above. Although the circuit description frequently disguises
the fact, it has already been shown that the frequency
doubIer is nothing more than a squaring circuit. Similarly the
variable gain amplifier is nothing more than a multiplier, with
the input signal applied at the X input and the control voltage
applied at the Y input.
I
V
O
1. Connect the ICL8013 in the Divider configuration.
2. Adjust Z
3. Convert to the Square Root configuration by connecting
4. With Z
Z
OU T
IN
(0V TO + 10V)
=
of Divider Trimming Procedure.
X
the output node.
Y
X
X
IN
IN
IN
=
IN
FIGURE 10A. SQUARE ROOT BLOCK DIAGRAM
to the output and inserting a diode between Pin 4 and
FIGURE 10B. ACTUAL CIRCUIT CONNECTION
–
×
Y
MODULATOR
IN
IN
Y
10Z
OS
IN
= 0V adjust Z
X
IN
, Y
IN
=
6
3
1
– (
OS
X
7
OS
V
OUT
, X
10
ICL8013
Y
OS
OS
I
O
)
2
, and Gain using Steps 1 through 6
= V
OS
Z
9
=
OS
O
I
10Z
Z
for zero output voltage.
2
IN
Z
R =
1N4148
4
OP AMP
GAIN
10
1
V
OUTPUT = -√10Z IN
OUT
5K
7.5K
= -√10Z
IN