Data Sheet AD532
Rev. E | Page 11 of 14
APPLICATIONS
The performance and ease of use of the AD532 is achieved through
the laser trimming of thin film resistors deposited directly on
the monolithic chip. This trimming on the chip technique provides
a number of significant advantages in terms of cost, reliability,
and flexibility over conventional in package trimming of off the
chip resistors mounted or deposited on a hybrid substrate.
Trimming on the chip eliminates the need for a hybrid substrate
and the additional bonding wires that are required between the
resistors and the multiplier chip. By trimming more appropriate
resistors on the AD532 chip itself, the second input terminals
that were committed to external trimming networks have been
freed to allow fully differential operation at both the X and Y
inputs. Further, the requirement for an input attenuator to
adjust the gain at the Y input has been eliminated, letting the
user take full advantage of the high input impedance properties
of the input differential amplifiers. Therefore, the AD532 offers
greater flexibility for both algebraic computation and transducer
instrumentation applications.
Provision for fine trimming the output voltage offset has been
included. This connection is optional, however, as the AD532 has
been factory trimmed for total performance as described in the
listed specifications.
REPLACING OTHER IC MULTIPLIERS
Existing designs using IC multipliers that require external
trimming networks can be simplified using the pin for pin
replaceability of the AD532 by merely grounding the X
2
, Y
2
,
and V
OS
terminals. The V
OS
terminal must always be grounded
when unused.
Multiplication
Z
OUT
AD532
X
1
X
2
Y
1
Y
2
V
OUT
V
OS
20kΩ
+V
S
–V
S
V
OUT
=
(X
1
– X
2
) (Y
1
– Y
2
)
10V
(OPTIONAL)
00502-013
Figure 14. Multiplier Connection
For operation as a multiplier, the AD532 must be connected as
shown in Figure 14. The inputs can be fed differentially to the X
and Y inputs or single-ended by simply grounding the unused
input. Connect the inputs according to the desired polarity in
the output. The Z terminal is tied to the output to close the
feedback loop around the op amp (see Figure 1). The offset adjust
V
OS
is optional and is adjusted when both inputs are zero volts
to obtain zero out, or to null other system offsets.
Squaring
AD532
X
1
X
2
Y
1
Y
2
V
OUT
20kΩ
+V
S
–V
S
+V
S
–V
S
V
OS
V
OUT
=
V
IN
2
10V
(OPTIONAL)
Z
OUT
V
IN
00502-014
Figure 15. Squarer Connection
The squaring circuit in Figure 15 is a simple variation of the
multiplier. The differential input capability of the AD532, however,
can obtain a positive or negative output response to the input, a
useful feature for control applications, as it might eliminate the
need for an additional inverter somewhere else.
Division
AD532
20kΩ
(X
0
)
47kΩ
2.2kΩ
10kΩ
1kΩ
(SF)
+V
S
–V
S
+V
S
–V
S
V
OUT
=
10VZ
X
Z
OUT
Z
V
OUT
X
X
1
X
2
Y
1
Y
2
00502-015
Figure 16. Divider Connection
The AD532 can be configured as a two-quadrant divider by
connecting the multiplier cell in the feedback loop of the op
amp and using the Z terminal as a signal input, as shown in
Figure 16. It should be noted, however, that the output error is
given approximately by 10 V ε
m
/(X
1
− X
2
), where ε
m
is the total
error specification for the multiply mode and bandwidth by f
m
×
(X
1
− X
2
)/10 V, where f
m
is the bandwidth of the multiplier.
Further, to avoid positive feedback, the X input is restricted to
negative values. Thus, for single-ended negative inputs (0 V to
−10 V), connect the input to X and the offset null to X
2
; for single-
ended positive inputs (0 V to +10 V), connect the input to X
2
and the offset null to X
1
. For optimum performance, gain (SF)
and offset (X
0
) adjustments are recommended as shown and
explained in Table 5.
For practical reasons, the useful range in denominator input is
approximately 500 mV ≤ |(X
1
− X
2
)| ≤ 10 V. The voltage offset
adjust (V
OS
), if used, is trimmed with Z at zero and (X
1
− X
2
) at
full scale.
