Datasheet

MAX4289
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
input common-mode voltage range extends from V
CC
-
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 5kΩ 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
+0.4mV to (V
CC
- 0.2mV) with a 100kΩ 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 _______________________________________________________________________________________
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
76V
CC
Positive Supply. Bypass with a 0.1µF capacitor to GND.
200µs/div
IN
500mV/div
OUT
500mV/div
V
IN
= 2.0V
f
IN
= 1kHz
R
L
= 100kΩ
Figure 1. Rail-to-Rail Input/Output Voltage Range
0
5
15
10
20
25
021 3456
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (µA)
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
Figure 2. I
CC
vs. V
CC
Over the Temperature Range