AD8207

Rev. 0 | Page 13 of 16

EXTERNAL REFERENCED OUTPUT

Tying both reference pins together and to an external reference

produces an output equal to the reference voltage when there is

no differential input (see Figure 30). 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. The reference pins are connected to the positive input

of the main amplifier via precision-trimmed 100 kΩ resistors.

Therefore, it is recommended that a low impedance voltage is

always be used to set the reference voltage. If external resistors

be a mismatch with the internal trimmed resistors, leading to

offset gain accuracy reduction.

RANGE

V+

5V

REF

+IN

–IN

OUT

VOLTAGE

REFERENCE

GND

AD8207

ZERO

DRIFT

2.5V

Figure 30. External Referenced Output, V+ = 5 V

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 dif-

ferential input (see Figure 31). 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.

RANGE

V+

5V

REF

+IN

–IN

OUT

GND

AD8207

ZERO

DRIFT

Figure 31. Splitting the Supply, V+ = 5 V

SPLITTING AN EXTERNAL REFERENCE

In Figure 32, an external reference is divided by 2 with an

V+

5V

REF

+IN

–IN

OUT

VOLTAGE

REFERENCE

GND

AD8207

ZERO

DRIFT

5V

RANGE

Figure 32. Splitting an External Reference, V+ = 5 V