AD830

REV. A

–10–

INTERFACING THE INPUT

Common-Mode Voltage Range

The common-mode range of the AD830 is defined by the am-

plitude of the differential input signal and the supply voltage.

ally applied to a symmetrical differential signal centered about a

particular voltage as illustrated by the diagram in Figure 23.

This is the meaning implied here for common-mode voltage.

The internal circuitry establishes the maximum allowable volt-

age on the input or feedback pins for a given supply voltage.

This constraint and the differential input voltage sets the

common-mode voltage limit. Figure 24 shows a curve of the

common-mode voltage range vs. differential voltage for three

supply voltage settings.

Figure 23. Common-Mode Definition

15

0

2.0

3

0

6

9

12

1.6

1.2

0.8

0.4

+V

CM

±15V = V

S

±10V = V

S

±5V = V

S

+V

CM

+V

CM

–V

CM

–V

CM

–V

CM

DIFFERENTIAL INPUT VOLTAGE – V

PEAK

Figure 24. Input Common-Mode Voltage Range vs.

Differential Input Voltage

Differential Voltage Range

The maximum applied differential voltage is limited by the clip-

ping range of the input stages. This is nominally set at 2.4 volts

magnitude and depicted in the crossplot (X-Y) photo of Figure

25. The useful linear range of the input stages is set at 2 volts,

but is actually a function of the distortion required for a particu-

lar application. The distortion increases for larger differential

input voltages. A plot of relative distortion versus input differen-

tial voltage is shown in Figures 8 and 11 in the Typical Charac-

teristics section. The distortion characteristics could impose a

secondary limit to the differential input voltage for high accu-

racy applications.

10

90

100

0%

1V

1V

Figure 25. Clipping Behavior

15

0

20

3

0

6

9

12

16

12

8

4

SUPPLY VOLTAGE – Volts

V

P

V

Figure 26. Maximum Output Swing vs. Supply