Data Sheet

AD8541/AD8542/AD8544

THEORY OF OPERATION

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Rev. H | 13 of 18

NOTES ON THE AD854X AMPLIFIERS

The AD8541/AD8542/AD8544 amplifiers are improved perform-

ance, general-purpose operational amplifiers. Performance has

been improved over previous amplifiers in several ways, including

lower supply current for 1 MHz gain bandwidth, higher output

current, and better performance at lower voltages.

Lower Supply Current for 1 MHz Gain

Bandwidth

The AD854x series typically uses 45 µA of current per amplifier,

which is much less than the 200 µA to 700 µA used in earlier

generation parts with similar performance. This makes the AD854x

series a good choice for upgrading portable designs for longer

battery life. Alternatively, additional functions and performance can

be added at the same current drain.

Higher Output Current

At 5 V single supply, the short-circuit current is typically 60 µA.

Even 1 V from the supply rail, the AD854x amplifiers can provide a

30 mA output current, sourcing, or sinking.

Sourcing and sinking are strong at lower voltages, with 15 mA

available at 2.7 V and 18 mA at 3.0 V. For even higher output

currents, see the AD8541/AD8542/AD8544 parts for output currents

to 250 mA. Information on these parts is available from your

Analog Devices, Inc. representative, and data sheets are available

at www.analog.com.

Better Performance at Lower Voltages

The AD854x family of parts was designed to provide better ac

performance at 3.0 V and 2.7 V than previously available parts.

Typical gain bandwidth product is close to 1 MHz at 2.7 V. Voltage

gain at 2.7 V and 3.0 V is typically 500,000. Phase margin is

typically over 60°C, making the part easy to use.