Low-Power Shutdown Mode
All parts feature a low-power shutdown mode that is
activated by driving the SHDN input low. Placing the
amplifier in shutdown mode reduces the quiescent sup-
ply current to 560µA and places the output into a high-
impedance state, typically 35kΩ. By tying the outputs of
several devices together and disabling all but one of
the paralleled amplifiers’ outputs, multiple devices may
be paralleled to construct larger switch matrices.
For MAX4310/MAX4311/MAX4312 application circuits
operating with a closed-loop gain of +2V/V or greater,
consider the external-feedback network impedance of
all devices used in the mux application when calculat
-
ing the total load on the output amplifier of the active
device. The MAX4313/MAX4314/MAX4315 have a fixed
gain of +2V/V that is internally set with two 500Ω thin-
film resistors. The impedance of the internal feedback
resistors must be taken into account when operating
multiple MAX4313/MAX4314/MAX4315s in large multi-
plexer applications. For normal operation, drive SHDN
high. If the shutdown function is not used, connect
SHDN to V
CC
.
Layout and Power-Supply Bypassing
The MAX4310–MAX4315 have very high bandwidths and
consequently require careful board layout, including the
possible use of constant-impedance microstrip or
stripline techniques.
To realize the full AC performance of these high-speed
amplifiers, pay careful attention to power-supply bypass-
ing and board layout. The PC board should have at least
two layers: a signal and power layer on one side, and a
large, low-impedance ground plane on the other side.
The ground plane should be as free of voids as possible,
with one exception: the feedback (FB) should have as low
a capacitance to ground as possible. Therefore, layers
that do not incorporate a signal or power trace should not
have a ground plane.
Whether or not a constant-impedance board is used, it is
best to observe the following guidelines when designing
the board:
1) Do not use wire-wrapped boards (they are too
inductive) or breadboards (they are too capacitive).
2) Do not use IC sockets; they increase parasitic
capacitance and inductance.
3) Keep signal lines as short and straight as possible.
Do not make 90° turns; round all corners.
4) Observe high-frequency bypassing techniques to
maintain the amplifier’s accuracy and stability.
5) Use surface-mount components. They generally
have shorter bodies and lower parasitic reactance,
yielding better high-frequency performance than
through-hole components.
MAX4310–MAX4315
High-Speed, Low-Power, Single-Supply
Multichannel, Video Multiplexer-Amplifiers
______________________________________________________________________________________ 13
20
-160
0 50 100 150 300 350 500
-100
-120
0
LOGIC-LOW THRESHOLD (mV ABOVE V
E
E
)
INPUT CURRENT (µA)
200 250 400 450
-60
-140
-
20
-40
-80
Figure 2. Logic-Low Input Current vs. V
IL
(
SHDN
, A0, A1, A2)
OUT
IN-
SHDN, A0, A1, A2
IN+
10kΩ
LOGIC INPUT
MAX431_
Figure 3. Circuit to Reduce Logic-Low Input Current
0
-10
0
50 100 150 300 350 500
-7
-8
-1
LOGIC-LOW THRESHOLD (mV ABOVE V
EE
)
INPUT CURRENT ( µA)
200 250 400 450
-3
-5
-
9
-
2
-4
-6
Figure 4. Logic-Low Input Current vs. V
IL
with 10kΩ Series
Resistor
