Datasheet

AD8205 Data Sheet
Rev. | Page 10 of 12
EXTERNAL REFERENCE OUTPUT
Tying both pins together and to a reference produces an output
at the reference voltage when there is no differential input (see
Figure 16). The output moves down from the reference voltage
when the input is negative relative to the −IN pin and up when
the input is positive relative to the −IN pin.
04315-0-015
AD8205
+IN
–IN
NC
NC = NO CONNECT
GND
V+
OUT
V
REF
1
V
REF
2
2.5V
VOLTAGE
REFERENCE
Figure 16. External Reference Output
SPLITTING THE SUPPLY
By tying one reference pin to V+ and the other to the ground
pin, the output is set at half of the supply when there is no
differential input (see Figure 17). The benefit is that no external
reference is required to offset the output for bidirectional
current measurement. This creates a midscale offset that is
ratiometric to the supply, which means that if the supply increases
or decreases, the output remains at half the supply. For example, if
the supply is 5.0 V, the output is at half scale or 2.5 V. If the supply
increases by 10% (to 5.5 V), the output goes to 2.75 V.
04315-0-016
AD8205
+IN
–IN
NC
NC = NO CONNECT
GND
V+
OUT
V
REF
1
V
REF
2
Figure 17. Split Supply
SPLITTING AN EXTERNAL REFERENCE
In this case, an external reference is divided by 2 with an
accuracy of approximately 0.5% by connecting one V
REF
pin to
ground and the other V
REF
pin to the reference (see Figure 18).
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AD8205
+IN
–IN
NC
NC = NO CONNECT
GND
V+
OUT
V
REF
1
V
REF
2
5V
VOLTAGE
REFERENCE
Figure 18. Split External Reference
D