Datasheet

ADR360/ADR361/ADR363/ADR364/ADR365/ADR366
Rev. D | Page 17 of 20
APPLICATIONS INFORMATION
BASIC VOLTAGE REFERENCE CONNECTION
The circuit in Figure 33 illustrates the basic configuration for
the ADR36x family. Decoupling capacitors are not required for
circuit stability. The ADR36x family is capable of driving
capacitive loads from 0 μF to 10 μF. However, a 0.1 μF ceramic
output capacitor is recommended to absorb and deliver the
charge, as is required by a dynamic load.
1
2
3
NC
GND
V
IN
ADR36x
5
4
TRIM
V
OUT
INPUT
0.1µF
OUTPUT
0.1µF
05467-025
Figure 33. Basic Configuration for the ADR36x Family
Stacking Reference ICs for Arbitrary Outputs
Some applications require two reference voltage sources, which
are a combined sum of standard outputs. Figure 34 shows how
this stacked output reference can be implemented.
05467-026
NC
NC
GND
GND
V
IN
V
IN
ADR36x
ADR36x
TRIM
TRIM
V
OUT
V
OUT
1
1
2
2
3
3
5
5
4
4
V
OUT2
V
OUT1
V
IN
C1
0.1µF
C2
0.1µF
Figure 34. Stacking Voltage References with the ADR36x
Two reference ICs are used and fed from an unregulated input,
V
IN
. The outputs of the individual ICs are connected in series,
which provides two output voltages, V
OUT1
and V
OUT2
. V
OUT1
is
the terminal voltage of U1, and V
OUT2
is the sum of this voltage
and the terminal voltage of U2. U1 and U2 are chosen for the
two voltages that supply the required outputs (see Table 10). For
example, if both U1 and U2 are ADR361s, V
OUT1
is 2.5 V and
V
OUT2
is 5.0 V.
Table 10. Output
U1/U2 V
OUT1
(V) V
OUT2
(V)
ADR361/ADR365 2.5 7.5
ADR361/ADR361 2.5 5.0
ADR365/ADR361 5 7.5
Negative Precision Reference Without Precision
Resistors
A negative reference is easily generated by adding an op amp,
A1 (see Figure 35). V
OUTF
and V
OUTS
are at virtual ground and
therefore the negative reference can be taken directly from the
output of the op amp. The op amp must be dual-supply, low
offset, and rail-to-rail if the negative supply voltage is close to
the reference output.
05467-027
NC
GND
V
IN
ADR36x
TRIM
V
OUT
1
2
3
+
5
4
–V
REF
–V
DD
+
V
DD
A1
Figure 35. Negative Reference