Detailed Description

The MAX4289 consumes ultra-low power (9µA supply

current typically) and has a rail-to-rail output stage that

is specifically designed for low-voltage operation. The

0.2V to ground, although full rail-to-rail input range is

possible with degraded performance. The input offset

voltage is typically 200µV. Low-operating supply volt-

age, low supply current, and rail-to-rail outputs make

this operational amplifier an excellent choice for preci-

sion or general-purpose, low-voltage, battery-powered

systems.

Rail-to-Rail Output Stage

The MAX4289 output stage can drive a 5k

Ω load and

still swing to within 7mV of the rails. Figure 1 shows the

output voltage swing of the MAX4289 configured as a

unity-gain buffer, powered from a single 2V supply volt-

age. The output for this setup typically swings from

Ω load.

Applications Information

Power-Supply Considerations

The MAX4289 operates from a single 1.0V to 5.5V supply

and consumes only 9µA of supply current. A high power-

supply rejection ratio of 75dB allows the amplifier to be

powered directly off a decaying battery voltage, simplify-

ing design and extending battery life. The MAX4289 is

ideally suited for single-cell battery-powered systems.

Figures 2 and 3 show the supply current and PSRR as a

function of supply voltage and temperature.

1.0V Micropower, SOT23, Operational Amplifier

6

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Pin Description

PIN

SO

SOT23

NAME

FUNCTION

1, 5, 8

5

N.C.

No Connection. Not internally connected.

2

4

IN-

Inverting Input

3

3

IN+

Noninverting Input

4

2

GND

Ground

6

1

OUT

Amplifier Output

76

Positive Supply. Bypass with a 0.1µF capacitor to GND.

200

µs/div

IN

500mV/div

OUT

500mV/div

Ω

Figure 1. Rail-to-Rail Input/Output Voltage Range

0

5

15

10

20

25

02

1

3

456

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

°C

°C

°C