ADR5041 Analog Devices, Inc., ADR5041 Datasheet - Page 12

• Manufacturer Part Number: ADR5041
• Description: Precision Micropower Shunt Mode Voltage References
• Manufacturer: Analog Devices, Inc.

ADR5040/ADR5041/ADR5043/ADR5044/ADR5045
Adjustable Precision Voltage Source
The ADR5040/ADR5041/ADR5043/ADR5044/ADR5045,
combined with a precision low input bias op amp such as the
AD8610, can be used to output a precise adjustable voltage.
Figure 22 illustrates the implementation of this application
using the ADR5040/ADR5041/ADR5043/ADR5044/ADR5045.
The output of the op amp, V
circuit, 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.
ADR5040/ADR5041/
ADR5043/ADR5044/
V
OUT
= (1 + R2/R1)V
ADR5045
Figure 22. Adjustable Voltage Source
R
V
BIAS
REF
GND
V
CC
REF
OUT
R1
(OPTIONAL)
AD8610
, is determined by the gain of the
R2
C1
V
OUT
= V
REF
(1 + R2/R1)
Rev. A | Page 12 of 16
Programmable Current Source
By using just a few ultrasmall and inexpensive parts, it is possible
to build a programmable current source, as shown in Figure 23.
The constant voltage on the gate of the transistor sets the current
through the load. Varying the voltage on the gate changes the
current. The
interface, and the
amp. Each incremental step of the digital potentiometer increases
or decreases the voltage at the noninverting input of the op amp.
Therefore, this voltage varies with respect to the reference
voltage.
R
ADR5040/
ADR5041/
ADR5043/
ADR5044/
ADR5045
BIAS
AD5247
Figure 23. Programmable Current Source
AD8601
AD5247
is a digital potentiometer with I
is a precision rail-to-rail input op
V
DD
AD8601
V+
V–
R
SENSE
2
C® digital
I
LOAD