ADR520/ADR525/ADR530/ADR540/ADR550

Rev. E | Page 12 of 1

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Stacking the ADR520/ADR525/ADR530/ADR540/ADR550

for User-Definable Outputs

Multiple ADR520/ADR525/ADR530/ADR540/ADR550 parts

can be stacked to allow the user to obtain a desired higher voltage.

Figure 22 shows three ADR550s configured to give 15 V. The bias

bias current flows through all the shunt references in series.

is calculated in the same manner as before. Parts of different

voltages can also be added together. For example, an ADR525

and an ADR550 can be added together to give an output of

+7.5 V or −7.5 V, as desired. Note, however, that the initial

accuracy error is now the sum of the errors of all the stacked

parts, as are the temperature coefficients and output voltage

change vs. input current.

ADR550

+15V

R

ADR550

ADR550

GND

Figure 22. +15 V Output with Stacked ADR550s

ADR550

ADR550

ADR550

GND

–15V

R

Figure 23. −15 V Output with Stacked ADR550s

Adjustable Precision Voltage Source

The ADR520/ADR525/ADR530/ADR540/ADR550, combined

with a precision low input bias op amp, such as the AD8610,

can be used to output a precise adjustable voltage. Figure 24

illustrates the implementation of this application using the

ADR520/ADR525/ADR530/ADR540/ADR550. The output

which is completely dependent on the resistors, R1 and R2.

An additional capacitor, C1, in parallel with R2, can be added to

filter out high frequency noise. The value of C1 is dependent on

the value of R2.

ADR5xx

GND

R

R1

R2

C1

(OPTIONAL)

AD8610

Figure 24. Adjustable Voltage Source