Datasheet AD532 (Analog Devices) - 10

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AD532 Data Sheet AD532 PERFORMANCE CHARACTERISTICS
Multiplication accuracy is defined in terms of total error at 25°C
COMMON-MODE REJECTION
with the rated power supply. The value specified is in percent of The AD532 features differential X and Y inputs to enhance its full scale and includes XIN and YIN nonlinearities, feedback and flexibility as a computational multiplier/divider. Common-mode scale factor error. To this must be added such application rejection for both inputs as a function of frequency is shown in dependent error terms as power supply rejection, common- Figure 8. It is measured with X mode rejection and temperature coefficients (although worst 1 = X2 = 20 V p-p, (Y1 − Y2) = 10 V dc and Y case error over temperature is specified for the AD532S). Total 1 = Y2 = 20 V p-p, (X1 − X2) = 10 V dc. expected error is the rms sum of the individual components
DYNAMIC CHARACTERISTICS
because they are uncorrelated. The closed-loop frequency response of the AD532 in the multiplier Accuracy in the divide mode is only a little more complex. To mode typical y exhibits a 3 dB bandwidth of 1 MHz and rol s off achieve division, the multiplier cel must be connected in the at 6 dB/octave, thereafter. Response through all inputs is essentially feedback of the output op amp as shown in Figure 16. In this the same as shown in Figure 9. In the divide mode, the closed- configuration, the multiplier cell varies the closed-loop gain of loop frequency response is a function of the absolute value of the op amp in an inverse relationship to the denominator voltage. the denominator voltage as shown in Figure 10. Therefore, as the denominator is reduced, output offset, bandwidth, Stable operation is maintained with capacitive loads to 1000 pF and other multiplier cel errors are adversely affected. The divide in al modes, except the square root for which 50 pF is a safe error and drift are then εm × 10 V/(X1 − X2), where εm represents upper limit. Higher capacitive loads can be driven if a 100 Ω multiplier ful -scale error and drift and (X1 − X2) is the absolute resistor is connected in series with the output for isolation. value of the denominator.
POWER SUPPLY CONSIDERATIONS NONLINEARITY
Although the AD532 is tested and specified with ±15 V dc Nonlinearity is easily measured in percent harmonic distortion. supplies, the device may be operated at any supply voltage from The curves of Figure 5 and Figure 6 characterize output distortion ±10 V to ±18 V for the J and K versions, and ±10 V to ±22 V as a function of input signal level and frequency respectively, for the S version. The input and output signals must be reduced with one input held at plus or minus 10 V dc. In Figure 6, the proportionately to prevent saturation; however, with supply sine wave amplitude is 20 V p-p. voltages below ±15 V, as shown in Figure 11. Because power
AC FEEDTHROUGH
supply sensitivity is not dependent on external null networks as in other conventionally nul ed multipliers, the power supply AC feedthrough is a measure of the multiplier’s zero suppression. rejection ratios are improved from 3 to 40 times in the AD532. With one input at zero, the multiplier output should be zero regardless of the signal applied to the other input. Feedthrough
NOISE CHARACTERISTICS
as a function of frequency for the AD532 is shown in Figure 7. The AD532 is sampled to assure that output noise wil have no It is measured for the condition VX = 0, VY = 20 V p-p and VY = 0, appreciable effect on accuracy. Typical spot noise vs. frequency VX = 20 V (p-p) over the given frequency range. It consists is shown in Figure 12. primarily of the second harmonic and is measured in mil ivolts peak-to-peak. Rev. E | Page 10 of 14 Document Outline Features Applications General Description Flexibility of Operation Functional Block Diagram Guaranteed Performance Over Temperature Advantages of On The Chip Trimming of The Monolithic AD532 Revision History Specifications Thermal Resistance Chip Dimensions And Bonding Diagram ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Functional Description AD532 Performance Characteristics Nonlinearity AC Feedthrough Common-Mode Rejection Dynamic Characteristics Power Supply Considerations Noise Characteristics Applications Replacing Other IC Multipliers Multiplication Squaring Division Square Root Additional Information Outline Dimensions Ordering Guide