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MAX44260/MAX44261

1.8V 15MHz Low-Offset,

Low-Power, Rail-to-Rail I/O Op Amps

Applications Information

Power-Up Autotrim

The ICs feature an automatic trim that self-calibrates the

voltage on power-up. This self-calibration feature allows

the device to eliminate input offset voltage effects due

to power supply and operating temperature variation

simply by cycling its power. The autotrim sequence takes

approximately 10ms to complete and is triggered by an

internal power-on-reset (POR) circuitry. During this time,

the inputs and outputs are put into high impedance and

left unconnected. The MAX44261 can also be forced into

a self-calibration cycle by pulling the CAL input low for

1ms. This input also puts the part into shutdown mode.

Shutdown Operation

The MAX44260 features an active-low shutdown mode

that puts both inputs and outputs into high impedance

and substantially lowers the quiescent current to less

than 1FA. Putting the output into high impedance allows

multiple outputs to be multiplexed onto a single output

line without the additional external buffers. The device

does not self-calibrate when exiting shutdown mode

and retains its power-up trim settings. Figure 3 shows

that the device also recovers from shutdown in under

30Fs.

The MAX44261 features a recalibrate input that acts the

same as the shutdown mode of the MAX44260. However,

when the input is pulled low, the device goes through a

self-calibration sequence again (Figure 3).

The shutdown logic levels of the devices are indepen-

dent of supply, allowing the shutdown feature of the

device to operate off of a 1.8V or 3.3V microcontroller,

regardless of supply voltage.

Rail-to-Rail Input/Output

The input voltage range of the ICs extends 100mV

mode voltage range allows the op amp to be used as

a buffer and as a differential amplifier in a wide-variety

of signal processing applications. Output voltage high/

applications. The high output current and capacitance

drive capability of the devices make them ideal as an

ADC driver and a line driver.

Figure 3. CAL vs. SHDN Input Operation

0V

0V

MAX44261

OUTPUT

30µs

10ms

AUTOTRIM

SEQUENCE

RECALIBRATED

AMPLIFIER

ACTIVE

MAX44260

OUTPUT

0V

FAST RECOVERY

AMPLIFIER

ACTIVE