AD8541/AD8542/AD8544
THEORY OF OPERATION
NOTES ON THE AD854X AMPLIFIERS
The AD8541/AD8542/AD8544 amplifiers are improved
performance, 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.
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
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
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.
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.
Rev. F | Page 13 of 20
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