M
Low-Power, +3V/+5V, 400MHz Single-Supply
Op Amps with Rail-to-Rail Outputs
______________________________________________________________________________________
17
Video Line Driver
The MAX4414
–
MAX4419 are designed to minimize dif-
ferential gain error and differential phase error to 0.03%/
0.15
°
respectively, making them ideal for driving video
loads. See Figure 4.
Active Filters
The low distortion and high bandwidth of the
MAX4414
–
MAX4419 make them ideal for use in active
filter circuits. Figure 5 is a 15MHz lowpass, multiple-
feedback active filter using the MAX4414.
ADC Input Buffer
Input buffer amplifiers can be a source of significant
errors in high-speed ADC applications. The input buffer
is usually required to rapidly charge and discharge the
ADC
’
s input, which is often capacitive (see
Output
Capacitive Loading and Stability
). In addition, since a
high-speed ADC
’
s input impedance often changes very
rapidly during the conversion cycle, measurement
accuracy must be maintained using an amplifier with
very low output impedance at high frequencies. The
combination of high speed, fast slew rate, low noise,
and a low and stable distortion over load make the
MAX4414
–
MAX4419 ideally suited for use as buffer
amplifiers in high-speed ADC applications.
Layout and Power-Supply Bypassing
These amplifiers operate from a single +2.7V to +5.5V
power supply. Bypass V
CC
to ground with a 0.1μF
capacitor as close to the pin as possible.
Maxim recommends using microstrip and stripline tech-
niques to obtain full bandwidth. Design the PC board
for a frequency greater than 1GHz to prevent amplifier
performance degradation due to board parasitics.
Avoid large parasitic capacitances at inputs and out-
puts. Whether or not a constant-impedance board is
used, observe the following guidelines:
Do not use wire-wrap boards due to their high induc-
tance.
Do not use IC sockets because of the increased par-
asitic capacitance and inductance.
Use surface-mount instead of through-hole compo-
nents for better high-frequency performance.
Use a PC board with at least two layers; it should be
as free from voids as possible.
Keep signal lines as short and as straight as possible.
Do not make 90
°
turns; round all corners.
Q
C
×
2
1
2
C
C
R
R
R
R
R
×
1
1
×
1
3
+
+
=
2
1
2
3
f
R
R
C
C
0
1
π
2
1
×
2
3
1
2
×
×
=
×
GAIN
R
R
=
2
1
R
O
75
IN
V
OUT
Z
O
= 75
(R
L
= R
O
+ R
TO
)
R
F
24
R
TO
75
R
TIN
75
MAX4414
Figure 4. Video Line Driver
