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AD8131

Rev. B | Page 17 of 20

INPUT COMMON-MODE VOLTAGE RANGE IN

SINGLE-SUPPLY APPLICATIONS

The AD8131 is optimized for level-shifting ground referenced

input signals. For a single-ended input this would imply, for

example, that the voltage at −DIN in Figure 39 would be zero

volts when the amplifier’s negative power supply voltage (at V−)

was also set to zero volts.

SETTING THE OUTPUT COMMON-MODE VOLTAGE

The AD8131’s VOCM pin is internally biased at a voltage

approximately equal to the midsupply point (average value of

the voltages on V+ and V−). Relying on this internal bias results

in an output common-mode voltage that is within about 25 mV

of the expected value.

In cases where more accurate control of the output common-

mode level is required, it is recommended that an external

source, or resistor divider (made up of 10 kΩ resistors), be used.

DRIVING A CAPACITIVE LOAD

A purely capacitive load can react with the pin and bondwire

inductance of the AD8131 resulting in high frequency ringing

in the pulse response. One way to minimize this effect is to

place a small resistor in series with the amplifier’s outputs as

shown in Figure 26.

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