Datasheet

capacitor placed close to the V
DD
pin. If operating from
dual supplies, bypass each supply to ground.
Good layout improves performance by decreasing the
amount of stray capacitance and noise at the op amp’s
inputs and output. To decrease stray capacitance, min-
imize PC board trace lengths and resistor leads, and
place external components close to the op amp’s pins.
Typical Application Circuit
The Typical Application Circuit shows the single
MAX4475 configured as an output buffer for the
MAX5541 16-bit DAC. Because the MAX5541 has an
unbuffered voltage output, the input bias current of the
op amp used must be less than 6nA to maintain 16-bit
accuracy. The MAX4475 has an input bias current of
only 150pA (max), virtually eliminating this as a source
of error. In addition, the MAX4475 has excellent open-
loop gain and common-mode rejection, making this an
excellent ouput buffer amplifier.
DC-Accurate Lowpass Filter
The MAX4475–MAX4478/MAX4488/MAX4489 offer a
unique combination of low noise, wide bandwidth, and
high gain, making them an excellent choice for active
filters up to 1MHz. The Typical Operating Circuit shows
the dual MAX4477 configured as a 5th order
Chebyschev filter with a cutoff frequency of 100kHz.
The circuit is implemented in the Sallen-Key topology,
making this a DC-accurate filter.
MAX4475–MAX4478/MAX4488/MAX4489
SOT23, Low-Noise, Low-Distortion,
Wide-Band, Rail-to-Rail Op Amps
11
Maxim Integrated
Typical Application Circuit
0 to +2.5V
OUTPUT
SHDN
8
4
CS
SCLK
DIN
2
3
SERIAL
INTERFACE
V
DD
DGND
REF
OUT
AGND
+5V
+2.5V
+5V
7
6
U1
MAX5541ESA
U2
MAX
4475AUA
Typical Operating Circuit
1
2
3
4
5
6
7
8
470pF
3.09kΩ
1%
3.83kΩ
1%
13.7kΩ
1%
7.87kΩ
1%
10.0kΩ
1%
10.0kΩ
1%
15.0kΩ
1%
7.15kΩ
1%
10.0kΩ
1%
0.1µF
220pF
220pF
220pF
220pF
5V
MAX4477
1/2
MAX4477
1/2