MAX4158ESA Maxim, MAX4158ESA Datasheet - Page 13

• Manufacturer Part Number: MAX4158ESA
• Description: 350MHz/250MHz / 2-Channel Video Multiplexer-Amplifiers
• Manufacturer: Maxim

A correctly terminated transmission line is purely resis-
tive and presents no capacitive load to the amplifier.
Consequently, the MAX4158/MAX4159/MAX4258/
MAX4259 are optimized for AC performance and are
not designed to drive highly capacitive loads. Reactive
loads will decrease phase margin and may produce
excessive ringing and oscillation (see Typical
Operating Characteristics ). The circuit of Figure 4
reduces this problem. The small (usually 5Ω to 20Ω)
isolation resistor R
prevents ringing and oscillation. At higher capacitive
loads, AC performance is limited by the interaction of
load capacitance with the isolation resistor.
Figure 3. Video Line Driver
75 CABLE
75 CABLE
R
G
75
R
T
75
R
T
FB
INO
INI
______________________________________________________________________________________
ISO
R
, placed before the reactive load,
F
Driving Capacitive Loads
MAX4158
MAX4159
MAX4258
MAX4259
OUT
75
R
T
75 CABLE
Video Multiplexer-Amplifiers
75
350MHz/250MHz, 2-Channel
R
T
Figure 4. Using an Isolation Resistor (R
Capacitive Loads
R
G
IN_
FB
R
F
MAX4158
MAX4159
MAX4258
MAX4259
OUT
ISO
) for High
R
ISO
C
L
R
13
L