MAX4144 Maxim, MAX4144 Datasheet - Page 14

• Manufacturer Part Number: MAX4144
• Description: High-Speed / Low-Distortion / Differential Line Receivers
• Manufacturer: Maxim

Losses are higher at higher frequencies, contributing to
severe pulse-edge rounding in digital applications. The
nominal impedance of twisted-pair telephone wire is
110Ω.
The MAX4145/MAX4146, with variable gain up to
+10V/V and +100V/V, respectively, can be used to
compensate for cable losses. In the graph shown in
Figure 8, the cable characteristics are such that the
video-chroma frequency loss is almost 15dB greater
High-Speed, Low-Distortion,
Differential Line Receivers
Figure 9. Circuit for Transmitting NTSC/PAL Video Over 1000 Feet of Twisted-Pair Telephone Line
14
__________________________________________________Typical Application Circuit
______________________________________________________________________________________
IN+
IN-
VIDEO INPUT
MAX4147
SENSE+
SENSE-
75
75
2
6
OUT+
OUT-
MAX4147ESD
V
V
CC
EE
8, 14
1, 7
R
R
9
T
T
13
TWISTED-PAIR-TO-COAX CABLE CONVERTER
10
12
0.1 F
0.1 F
1000 FEET
R
T
than the low-frequency loss. The losses can be com-
pensated for by using the RC-shaping network (Figure
9).
A 560Ω resistance and a 100pF capacitance shape the
MAX4146 gain to inversely match the frequency of the
1000 feet of telephone cable. The differential gain and
phase, using the circuit shown in Figure 9, is 0.55%
and 0.18°, respectively.
110
R
T
100pF
560
IN+
IN-
MAX4144
SENSE
2
3
5
6
MAX4146ESD
REF
V
V
CC
EE
1, 7
8, 14
OUT
13
9
0.1 F
0.1 F
75
11
COAX
75
75
VIDEO
OUTPUT
75
V
OUT