HA1-2556/883 INTERSIL [Intersil Corporation], HA1-2556/883 Datasheet - Page 13

• Manufacturer Part Number: HA1-2556/883
• Description: Wideband Four Quadrant Analog Multiplier (Voltage Output)
• Manufacturer: INTERSIL [Intersil Corporation]

DESIGN INFORMATION
The information contained in this section has been developed through characterization by Intersil Semiconductor and is for use as
application and design information only. No guarantee is implied.
Let’s first examine the Balance Concept as it applies to the
standard multiplier configuration (Figure 2).
Signals A and B are input to the multiplier and the signal W
is the result. By substituting the signal values into the Bal-
ance equation you get:
And solving for W:
Notice that the output (W) enters the equation in the feed-
back to the Z stage. The Balance Equation does not test for
stability, so remember that you must provide negative feed-
back. In the multiplier configuration, the feedback path is
connected to V
that takes place at the summing node just prior to the output
amplifier. Feedback is not restricted to the Z stage, other
feedback paths are possible as in the Divider Configuration
shown in Figure 3.
Inserting the signal values A, B and W into the Balance
Equation for the divider configuration yields:
Solving for W yields:
Notice that, in the divider configuration, signal B must remain
negative, then it will be multiplied by the V
positive feedback and the output will swing into the rail.
0 (positive) for the feedback to be negative. If signal B is
B
A
B
V
V
V
V
V
V
V
V
X
X
Y
Y
Y
Y
X
X
-
+
-
+
+
-
+
-
Z
1/5V
1/5V
–
+ input, not V
W
+
+
-
-
FIGURE 2. MULTIPLIER
+
+
-
-
A
FIGURE 3. DIVIDER
W
X
Y
Y
X
W
B
HA-2556
HA-2556
=
B
=
Z
A
----------- -
=
+
+
-. This is due to the inversion
5A
-----
=
-
-
B
5
5V
B
Z
5 W
Z
A
A
+
+
-
-
–
X-
A
V
V
input to produce
V
V
OUT
V
V
OUT
(Continued)
Z
Z
Z
Z
+
-
+
-
A
HA2556
W
W
8-19
Signals may be applied to more than one input at a time as
in the Squaring configuration in Figure 4:
Here the Balance equation will appear as:
Which simplifies to:
The last basic configuration is the Square Root as shown in
Figure 5. Here feedback is provided to both X and Y inputs.
The Balance equation takes the form:
Which equates to:
Application Circuits
The four basic configurations (Multiply, Divide, Square and
Square Root) as well as variations of these basic circuits
have many uses.
Frequency Doubler
For example, if ACos(
Square function, then it becomes a Frequency Doubler and
the equation takes the form:
And using some trigonometric identities gives the result:
A
ACos
V
V
V
V
FIGURE 5. SQUARE ROOT (FOR A > 0)
V
V
V
V
X
X
Y
Y
+
-
+
-
X
X
Y
Y
+
-
+
-
1/5V
W
1/5V
+
+
-
-
W
=
+
-
+
-
A
FIGURE 4. SQUARE
A 2
-----
10
Y
X
Y
X
W
HA-2556
W
) is substituted for signal A in the
HA-2556
–
1
A
ACos
=
W
=
+
+
+
-
Cos 2
-
Spec Number
A 2
-----
=
5
5A
=
Z
5 W
Z
5
A
A
–
+
-
+
-
A
V
=
V
V
V
OUT
V
V
Z
Z
OUT
+
-
Z
Z
5 W
+
-
511063-883
A
W
W