MAX4141 Datasheet, PDF (6/8 Pages) Maxim Integrated Products – 330MHz, 4x1 Precision Video Multiplexer

330MHz, 4x1 Precision Video Multiplexer
______________________________________________________________Pin Description
PIN
1
2, 4, 6
3
5
7
8
9
10
11
12
13
14
FUNCTION
IN0
GND
IN1
IN2
IN3
N.C.
EN
VEE
OUT
VCC
A1
A0
DESCRIPTION
Signal Input
Analog (Signal) Ground. Since inputs are isolated by these grounds, they should be as noise-free
as possible.
Signal Input
Signal Input
Signal Input
No Connect—not internally connected.
Output Enable and device shutdown. A logic high on this pin enables the output. A logic low
causes the output to assume a high-impedance state and reduces operating current.
Negative Power-Supply Voltage. Decouple to power ground.
Signal Output
Positive Power-Supply Voltage. Decouple to power ground.
Channel Selection Bit. See truth tables.
Channel Selection Bit. See truth tables.
_______________Detailed Description
The MAX4141 video switch is manufactured with
Maxim’s proprietary complementary bipolar process
that yields high bandwidth and low capacitance. To
maintain a wide bandwidth, the MAX4141 incorporates
a straightforward structure of input and output buffers.
Make-before-break switching is employed to reduce
noise and glitches, even when switching from part to
part in large arrays. The input buffers provide a con-
stant, high input impedance. And, they prevent the
make-before-break action from feeding back to the
input and causing noise and/or glitches.
The design of the switching mechanism limits the
inevitable glitch to within 13mVp-p. In addition, the
glitch pulse is positive to avoid confusion with any neg-
ative sync pulses.
Unity-gain output buffers isolate other inputs from the
switching action of large multiplex arrays. These buffers
can drive 5kΩ resistive loads. Load capacitance is lim-
ited only by system bandwidth requirements.
The MAX4141 does not contain buffer latches. The digi-
tal inputs control the switch transparently.
__________Applications Information
Grounding, Bypassing,
and PC Board Layout
In order to obtain the MAX4141’s full 330MHz bandwidth,
Microstrip and Stripline techniques are recommended in
most cases. To ensure your PC board does not degrade
the switch’s performance, it’s wise to design the board
for a frequency greater than 1GHz. Even with very short
runs, it’s good practice to use this technique at critical
points, such as inputs and outputs. Whether you use a
constant-impedance board or not, observe the following
guidelines when designing the board:
• Do not use wire-wrap boards, because they are too
inductive.
• Do not use IC sockets. They increase parasitic
capacitance and inductance.
• In general, surface-mount components have shorter
leads and lower parasitic reactance, and give better
high-frequency performance than through-hole com-
ponents.
• The PC board should have at least two layers, with
one side a signal layer and the other a ground plane.
• Keep signal lines as short and as straight as possi-
ble. Do not make 90° turns; round all corners.
• The ground plane should be as free from voids as
possible.
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