Datasheet

MAX44265
Rail-to-Rail, 200kHz Op Amp
with Shutdown in a Tiny, 6-Bump WLP
10 ______________________________________________________________________________________
Detailed Description
Featuring a maximized ratio of GBW to supply current,
low operating supply voltage, low input bias current,
and rail-to-rail inputs and outputs, the MAX44265 is an
excellent choice for precision or general-purpose, low-
current, low-voltage, battery-powered applications. This
CMOS device consumes an ultra-low 4µA (typ) supply
current and has a 200µV (typ) offset voltage. For addi-
tional power conservation, the IC features a low-power
shutdown mode that reduces supply current to 1nA
(typ) and puts the amplifier’s output in a high-imped-
ance state. This device is unity-gain stable with a
200kHz GBW product, driving capacitive loads up to
30pF. The capacitive load can be increased to 250pF
when the amplifier is configured for a 10V/V gain.
Rail-to-Rail Inputs and Outputs
The IC has a parallel-connected n- and p-channel dif-
ferential input stage that allows an input common-mode
voltage range that extends 100mV beyond the positive
and negative supply rails, with excellent common-mode
rejection. The IC is capable of driving the output to
within 5mV of both supply rails with a 100kΩ load. This
device can drive a 5kΩ load with swings to within 60mV
of the rails. Figure 1 shows the output voltage swing of
the IC configured as a unity-gain buffer powered from a
single 3V supply.
Low Input Bias Current
The IC features ultra-low 1pA (typ) input bias current.
The variation in the input bias current is minimal with
changes in the input voltage due to very high input
impedance (in the order of 1GΩ).
Applications Information
Driving Capacitive Loads
The IC’s amplifier is unity-gain stable for loads up to
30pF. However, the capacitive load can be increased
to 250pF when the amplifier is configured for a mini-
mum gain of 10V/V. Applications that require greater
capacitive-drive capability should use an isolation
resistor between the output and the capacitive load
(Figure 2). Also, in unity-gain applications with relatively
small R
L
(approximately 5kΩ), the capacitive load can
be increased up to 200pF.
Figure 1. Rail-to-Rail Output Voltage Range
RAIL-TO-RAIL OUTPUT VOLTAGE RANGE
200µs/div
IN_
3V
3V
0V
0V
1V/div
OUT_
1V/div
Figure 2. Using a Resistor to Isolate a Capacitive Load from
the Op Amp
MAX44265
R
ISO
C
L
R
L
A
V
= ≈ 1V/V
R
L
R
L
+ R
ISO