AD8271ARMZ-RL View Datasheet(PDF) - Analog Devices
Part Name
Description
Manufacturer
AD8271ARMZ-RL Datasheet PDF : 20 Pages
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AD8271
APPLICATIONS INFORMATION
The resistors and connections provided on the AD8271 offer
abundant versatility through the variety of configurations that
are possible.
DIFFERENCE AMPLIFIER CONFIGURATIONS
The AD8271 can be placed in difference amplifier configurations
with gains of ½, 1, and 2. Figure 45 through Figure 47 show
sample difference amplifier configurations referenced to ground.
P1 10kΩ
+IN
1
P2 10kΩ
2
P3 20kΩ
3
P4 20kΩ
4
10kΩ N3
10 –IN
10kΩ N2
9
10kΩ N1
8
OUT
7
–IN
=
+IN
GND
AD8271
OUT
5kΩ
10kΩ
10kΩ
5kΩ
GND
Figure 45. Gain = ½ Difference Amplifier, Referenced to Ground
+IN
NC
GND
P1 10kΩ
1
P2 10kΩ
2
P3 20kΩ
3
P4 20kΩ
4
10kΩ N3
10
–IN
10kΩ
10kΩ
N2
9
NC –IN
N1
8
=
+IN
OUT OUT
7
AD8271
10kΩ
10kΩ
10kΩ
10kΩ
GND
Figure 46. Gain = 1 Difference Amplifier, Referenced to Ground
+IN
GND
P1 10kΩ
1
P2 10kΩ
2
P3 20kΩ
3
P4 20kΩ
4
10kΩ N3
10
10kΩ N2
9
10kΩ N1
8
OUT
7
–IN
–IN
=
+IN
OUT
AD8271
OUT
10kΩ
5kΩ
5kΩ
10kΩ
GND
Figure 47. Gain = 2 Difference Amplifier, Referenced to Ground
The AD8271 can also be referred to a combination of reference
voltages. For example, the reference can be set at 2.5 V, using
just 5 V and GND. Some of the possible configurations are
shown in Figure 48 through Figure 50. Note that the output
is not internally tied to a feedback path, so any of the 10 kΩ
resistors on the inverting input can be used in the feedback
network. This flexibility allows for more efficient board lay-
out options.
P1 10kΩ
+IN
1
P2 10kΩ
–VS
2
P3 20kΩ
3
+VS P4 20kΩ
4
10kΩ N3
10 –IN
10kΩ N2
9
10kΩ N1
8
–IN
=
OUT +IN
OUT
7
AD8271
5kΩ
10kΩ
10kΩ
5kΩ
+VS + –VS
2
Figure 48. Gain = ½ Difference Amplifier, Referenced to Midsupply
P1 10kΩ
+IN
1
10kΩ N3
10
–IN
10kΩ
P2 10kΩ
NC
2
10kΩ N2
9
NC –IN 10kΩ
P3 20kΩ
–VS
3
10kΩ N1
8
=
10kΩ
+IN
P4 20kΩ
+VS
4
AD8271
OUT OUT
7
10kΩ
+VS + –VS
2
Figure 49. Gain = 1 Difference Amplifier, Referenced to Midsupply
P1 10kΩ
1
+IN P2 10kΩ
2
P3 20kΩ
–VS
3
P4 20kΩ
+VS
4
10kΩ
10kΩ
10kΩ
N3
10
N2
9
N1
8
OUT
7
+IN
–IN
=
+IN
OUT
AD8271
10kΩ
5kΩ
5kΩ
10kΩ
+VS + –VS
2
Figure 50. Gain = 2 Difference Amplifier, Referenced to Midsupply
Table 8. Pin Connections for Difference Amplifier Configurations
Gain and Reference
Gain of ½, Referenced to Ground
Gain of ½, Referenced to Midsupply
Gain of 1, Referenced to Ground
Gain of 1, Referenced to Midsupply
Gain of 2, Referenced to Ground
Gain of 2, Referenced to Midsupply
Pin 1
(P1)
+IN
+IN
+IN
+IN
+IN
+IN
Pin 2
(P2)
GND
−VS
NC
NC
+IN
+IN
Pin 3
(P3)
GND
+VS
GND
−VS
GND
−VS
Configuration
Pin 4
(P4)
Pin 8
(N1)
GND
OUT
+VS
OUT
GND
OUT
+VS
OUT
GND
OUT
+VS
OUT
Pin 9
(N2)
OUT
OUT
NC
NC
−IN
−IN
Pin 10
(N3)
−IN
−IN
−IN
−IN
−IN
−IN
Rev. 0 | Page 16 of 20
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