MAX4032 Maxim, MAX4032 Datasheet - Page 8

• Manufacturer Part Number: MAX4032
• Description: The MAX4032 5V, 6dB video buffer with sync-tip clamp, output sag correction, and low-power shutdown mode is available in tiny SOT23 and SC70 packages
• Manufacturer: Maxim

voltage is close to the rated voltage of the capacitor, a
film dielectric is recommended. Increasing the capaci-
tor value slows the clamp capture time. Values above
0.5µF should be avoided since they do not improve the
clamp’s performance.
The active sync-tip clamp also requires that the input
impedance seen by the input capacitor be less than
100Ω typically to function properly. This is easily met by
the 75Ω input resistor prior to the input-coupling capac-
itor and the back termination from a prior stage.
Insufficient input resistance to ground causes the
MAX4032 to appear to oscillate. Never operate the
MAX4032 in this mode.
The output of the MAX4032 can be AC- or DC-coupled
to the load. In the DC-coupled mode, the MAX4032
provides accurate sync-tip clamping for single-supply
operation and still can drive a 150Ω, back-terminated
load. In the AC-coupled mode, the MAX4032 allows the
use of minimal size capacitors to drive a back-terminat-
ed video load of 150Ω.
By shorting SAG to OUT, the device becomes an ampli-
fier with DC restore, optimally placing the video within
the dynamic range of the output. In this mode, the
MAX4032 can be used as the input conditioner for a
video signal, providing gain and biasing in single-sup-
ply applications. DC-coupling also improves the
MAX4032’s performance in terms of differential gain
and phase. This reflects the improvement in the low-fre-
quency response due to DC-coupling.
5V, 6dB Video Buffer with Sync-Tip Clamp,
Output Sag Correction, and 150nA Shutdown Current
8
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Output Coupling the MAX4032
DC-Coupling the Output
AC-Coupling the Output
The MAX4032’s output is configured to support AC-
coupling with minimal capacitance. This is called “sag
correction.” It refers to the improved bandwidth
achieved by using two smaller capacitors to replace a
single large capacitor shown in Figure 3.
The MAX4032 operates from a single 5V supply.
Bypass the supply with a 0.1µF capacitor as close to
the pin as possible. Maxim recommends using
microstrip and stripline techniques to obtain full band-
width. To ensure that the PC board does not degrade
the device’s performance, design it for a frequency
greater than 1GHz. Pay careful attention to inputs and
outputs to avoid large parasitic capacitance. Whether
or not you use a constant-impedance board, observe
the following design guidelines:
• Do not use wire-wrap boards; they are too inductive.
• Do not use IC sockets; they increase parasitic capac-
• Use surface-mount instead of through-hole compo-
• Use a PC board with at least two layers; it should be
• Keep signal lines as short and as straight as possible.
TRANSISTOR COUNT: 755
PROCESS: BiCMOS
itance and inductance.
nents for better, high-frequency performance.
as free from voids as possible.
Do not make 90° turns; round all corners.
Layout and Power-Supply Bypassing
Chip Information