AD598 Analog Devices, AD598 Datasheet
AD598
Available stocks
Related parts for AD598
AD598 Summary of contents
Page 1
... The position output can drive as much as 1000 feet of cable. 7. The AD598 may be used as a loop integrator in the design of simple electromechanical servo loops. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. ...
Page 2
... V rms 4.1 2.6 4.1 V rms rms 600 ppm rms 12 mA rms 60 mA 100 30 100 mV 20k 20 20k Hz 200 ppm/ C –50 dB 3.5 0.1 3.5 V rms 200 kHz 17 +70 C –40 +85 C AD598AD REV. A ...
Page 3
... S S Storage Temperature Range R Package . . . . . . . . . . . . . . . . . . . . . . . . . – +150 C D Package . . . . . . . . . . . . . . . . . . . . . . . . . – +150 C Operating Temperature Range AD598JR . . . . . . . . . . . . . . . . . . . . . . . . . . . . +70 C AD598AD . . . . . . . . . . . . . . . . . . . . . . . . . . – +85 C Lead Temperature Range (Soldering 60 sec +300 C Power Dissipation 1.2 W Derates Above + mW/ C REV 1.65% of full scale. Note that 1000 ppm of full scale equals 0.1% of full scale. ...
Page 4
... TEMPERATURE – C Figure 3. Gain and Offset CMRR vs. Temperature THEORY OF OPERATION A block diagram of the AD598 along with an LVDT (Linear Variable Differential Transformer) connected to its input is shown in Figure 5. The LVDT is an electromechanical trans- ducer whose input is the mechanical displacement of a core and whose output is a pair of ac voltages proportional to core posi- tion ...
Page 5
... The AD598 can easily be connected for dual or single supply operation as shown in Figures 7 and 12. The following general design procedures demonstrate how external component values are selected and can be used for any LVDT which meets AD598 input/output criteria. Parameters which are set with external passive components in- clude: excitation frequency and amplitude, AD598 system bandwidth, and the scale factor (V/inch) ...
Page 6
... SCHAEVITZ E100 LVDT Figure 7. Interconnection Diagram for Dual Supply Operation The AD598 signal input rms to 3.5 V rms for maximum AD598 linearity and minimum noise susceptibility. Select V fore, LVDT excitation voltage V V Check the power supply voltages by verifying that the peak values of V ...
Page 7
... Farad Hz/250 Hz = 0.4 F See Figures 13, 14 and 15 for more information about AD598 bandwidth and phase characterization order to Compute R2, which sets the AD598 gain or full- scale output range, several pieces of information are needed: a. LVDT sensitivity Full-scale core displacement ...
Page 8
... The figures are transfer functions with the input to be considered as a sinusoidally varying mechanical posi- tion and the output as the voltage from the AD598; the units of the transfer function are volts per inch. The value of C2, C3 and C4, from Figure 7, are all equal and designated as a parameter in the figures ...
Page 9
... Figure 18. LVDT Secondary Voltage vs. Core Displacement 1 10 Thermal Shutdown and Loading Considerations The AD598 is protected by a thermal overload circuit. If the die temperature reaches 165 C, the sine wave excitation amplitude gradually reduces, thereby lowering the internal power dissipa- tion and temperature. Due to the ratiometric operation of the decoder circuit, only small errors result from the reduction of the excitation ampli- tude ...
Page 10
... The value can be calculated using one of two sepa- rate methods. First, a potentiometer may be connected between Pins 18 and 19 of the AD598, with the wiper connected to –V . This gives a small offset of either polarity; and the SUPPLY value can be calculated using Step 10 of the design procedures ...
Page 11
... MECHANICAL POSITION INPUT Figure 21. Multiple LVDTs—Synchronous Operation HIGH RESOLUTION POSITION-TO-FREQUENCY CIRCUIT In the circuit shown in Figure 22, the AD598 is combined with an AD652 voltage-to-frequency (V/F) converter to produce an effective, simple data converter which can make high resolution measurements. This circuit transfers the signal from the LVDT to the V/F con- verter in the form of a current, thus eliminating the errors nor- mally caused by the offset voltage of the V/F converter ...
Page 12
... This circuit is both simple and inexpensive. It has the advantage that two LVDTs may be driven from one AD598, but the disad- vantage is that the scale factor of each LVDT may not match exactly. This causes the workpiece thickness measurement to vary depending upon its absolute position in the differential gage head ...
Page 13
... GND IN4740A 10V POWER SUPPLY + V 0 OFFSET OFFSET 2 17 SIG REF V 10V OUT 16 SIG OUT FULL SCALE R2 80.9k 15 FEEDBACK 0. OUT FILT 13 A1 FILT 0 FILT AD598 )+(V –V ) • 500 A • )+( ...
Page 14
... AD598 80. 0 OFFSET 1 OFFSET SIG REF 80.9k 16 SIG OUT 15 FEEDBACK 0.33 F OUT FILT FILT 0 FILT AD598 –V V – • • • 500 10V OUT REV. A ...
Page 15
... ALTERNATE HALF-BRIDGE TRANSDUCER CIRCUIT This circuit suffers from similar accuracy problems to those and V input voltages mentioned in the previous circuit description. In this circuit the B V input signal to the AD598 really and truly is a linear function A and V input volt- of core position, and the input signal tation voltage level ...
Page 16
... AD598 OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 20-Pin Sized Brazed Ceramic DIP 20-Lead Wide Body Plastic SOIC (R) Package –16– REV. A ...