1-Input/4-Output
Video Distribution Amplifiers
+5VDC
0.1µF
N.C.
1
VCCO
2
-5VDC
+5VDC
* TO TERMINATE TRANSMISSION LINE
75Ω*
75Ω*
0.1µF
75Ω*
75Ω*
0.1µF
75Ω*
OUT1
3
GND
4
OUT2
5
VEEO
6
VEEO
7
OUT3
8
GND
9
OUT4
10
VCCO
11
N.C.
12
Figure 1. MAX4137 Typical Operating Circuit
MAX4137
N.C.
24
SW1
SEL1
23
OUT1
OUT2
SW2
SEL2
22
AGND
21
VIDEO
IN+
IN
20
IN
75Ω∗
OUT3
OUT4
RF
RG VEEI
19
AGND
18
N.C.
17
VCCI
16
SW3
SEL3
15
SW4
SEL4
14
N.C.
13
-5VDC
0.1µF
+5VDC
0.1µF
__________Applications Information
Grounding, Bypassing,
and PC Board Layout
To obtain the MAX4137/MAX4138’s full 185MHz band-
width, Microstrip and Stripline techniques are recom-
mended in most cases. To ensure the PC board does
not degrade the amplifier’s performance, design the
board for a frequency greater than 1GHz. Even with
very short traces, use these techniques at critical
points, such as inputs and outputs. Whether you use a
constant-impedance board or not, observe the follow-
ing guidelines when designing the board:
• Do not use wire-wrap boards. 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, giving 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 straight as possible.
Do not make 90° turns; round all corners.
• The ground plane should be as free from voids as
possible.
8 _______________________________________________________________________________________