AD532 Analog Devices, AD532 Datasheet - Page 5

• Manufacturer Part Number: AD532
• Description: Internally Trimmed Integrated Circuit Multiplier
• Manufacturer: Analog Devices

DYNAMIC CHARACTERISTICS
The closed loop frequency response of the AD532 in the multi-
plier mode typically exhibits a 3 dB bandwidth of 1 MHz and
rolls off at 6 dB/octave thereafter. Response through all inputs is
essentially the same as shown in Figure 7. In the divide mode,
the closed loop frequency response is a function of the absolute
value of the denominator voltage as shown in Figure 8.
Stable operation is maintained with capacitive loads to 1000 pF
in all modes, except the square root for which 50 pF is a safe
upper limit. Higher capacitive loads can be driven if a 100
resistor is connected in series with the output for isolation.
POWER SUPPLY CONSIDERATIONS
Although the AD532 is tested and specified with 15 V dc
supplies, it may be operated at any supply voltage from 10 V
to 18 V for the J and K versions, and 10 V to 22 V for the S
version. The input and output signals must be reduced propor-
tionately to prevent saturation; however, with supply voltages
below 15 V, as shown in Figure 9. Since power supply sensitiv-
ity is not dependent on external null networks as in the AD530
and other conventionally nulled multipliers, the power supply
rejection ratios are improved from 3 to 40 times in the AD532.
REV. B
Figure 8. Frequency Response, Dividing
Figure 9. Signal Swing vs. Supply
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NOISE CHARACTERISTICS
All AD532s are screened on a sampling basis to assure that
output noise will have no appreciable effect on accuracy. Typi-
cal spot noise vs. frequency is shown in Figure 10.
APPLICATIONS CONSIDERATIONS
The performance and ease of use of the AD532 is achieved
through the laser trimming of thin-film resistors deposited di-
rectly on the monolithic chip. This trimming-on-the-chip tech-
nique 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.
First and foremost, 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 trim-
ming more appropriate resistors on the AD532 chip itself, the
second input terminals that were once committed to external
trimming networks (e.g., AD530) 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. Thus, the AD532 offers greater flexibility for both
algebraic computation and transducer instrumentation
applications.
Finally, 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 trim-
ming networks (such as the AD530) can be simplified using the
pin-for-pin replaceability of the AD532 by merely grounding
the X
be grounded when unused.)
2
, Y
2
and V
Figure 10. Spot Noise vs. Frequency
OS
terminals. (The V
OS
terminal should always
AD532