Datasheet ADR525, ADR530, ADR550 (Analog Devices) - 10

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ADR525/ADR530/ADR550 Stacking the ADR525/ADR530/ADR550 for Adjustable Precision Voltage Source User-Definable Outputs
The ADR525/ADR530/ADR550, combined with a precision low Multiple ADR525/ADR530/ADR550 parts can be stacked to input bias op amp, such as the AD8610, can be used to output a allow the user to obtain a desired higher voltage. Figure 18 shows precise adjustable voltage. Figure 20 illustrates the implementation three ADR550s configured to give 15 V. The bias resistor, RBIAS, is of this application using the ADR525/ADR530/ADR550. The chosen using Equation 3; note that the same bias current flows output of the op amp, VOUT, is determined by the gain of the circuit, through all the shunt references in series. Figure 19 shows three which is completely dependent on the resistors, R1 and R2. ADR550s stacked to give −15 V. RBIAS is calculated in the same VOUT = VREF (1 + R2/R1) manner as for Figure 18. Parts of different voltages can also be added together. For example, an ADR525 and an ADR550 can An additional capacitor, C1, in parallel with R2, can be added to be added together to give an output of +7.5 V or −7.5 V, as filter out high frequency noise. The value of C1 is dependent on desired. Note, however, that the initial accuracy error is now the the value of R2. sum of the errors of all the stacked parts, as are the temperature
VS
coefficients and output voltage change vs. input current.
R +VDD VREF R AD8610 V +15V OUT = VREF (1+R2/R1) ADR550 ADR5xx R2 ADR550 ADR550
2
R1 C1
-02
(OPTIONAL)
1
GND
50 3 04 02 1- Figure 18. +15 V Output with Stacked ADR550s
GND
0450 Figure 20. Adjustable Voltage Source
ADR550 GND ADR550 ADR550 –15V R
4 2 0 1-
–VDD
50 04 Figure 19. −15 V Output with Stacked ADR550s Rev. F | Page 10 of 12 Document Outline FEATURES APPLICATIONS PIN CONFIGURATION GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ADR525 ELECTRICAL CHARACTERISTICS ADR530 ELECTRICAL CHARACTERISTICS ADR550 ELECTRICAL CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PARAMETER DEFINITIONS TEMPERATURE COEFFICIENT THERMAL HYSTERESIS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION APPLICATIONS Precision Negative Voltage Reference Output Voltage Trim Stacking the ADR525/ADR530/ADR550 for User-Definable Outputs Adjustable Precision Voltage Source OUTLINE DIMENSIONS ORDERING GUIDE