MAX9129 Maxim, MAX9129 Datasheet - Page 7

• Manufacturer Part Number: MAX9129
• Description: The MAX9129 is a quad bus low-voltage differential signaling (BLVDS) driver with flow-through pinout
• Manufacturer: Maxim

The MAX9129 is a 200Mbps quad differential BLVDS
driver designed for multipoint, heavily loaded backplane
applications. This device accepts LVTTL/LVCMOS input
levels and translates them to output levels of 250mV to
450mV into a 27Ω load. The flow-through pinout simpli-
fies board layout and reduces the potential for crosstalk
between single-ended inputs and differential outputs.
Transition times are designed to reduce reflections, yet
enable high data rates. The MAX9129 can be used in
conjunction with standard quad LVDS receivers, such
Figure 4. Driver High-Impedance Delay Test Circuit
Figure 5. Driver High-Impedance Delay Waveform
GENERATOR
GND
V
CC
50Ω
EN WHEN EN = 0 OR OPEN
OUT_+ WHEN IN_ = V
OUT_- WHEN IN_ = V
EN
EN
_______________________________________________________________________________________
OUT_+ WHEN IN_ = 0
OUT_- WHEN IN_ = 0
EN WHEN EN = V
1/4 MAX9129
Detailed Description
IN_
CC
CC
CC
C
C
L
L
R
R
L
L
/2
/2
OUT_+
OUT_-
t
t
PHZ
PLZ
50%
50%
+1.2V
Quad Bus LVDS Driver with
50%
50%
as the MAX9121, to implement full-duplex multipoint
buses more efficiently than with transceivers.
The characteristic impedance of a differential PC board
trace is uniformly reduced when equal capacitive loads
are attached at equal intervals (provided the transition
time of the signal being driven on the trace is longer
than the delay between loads). This kind of loading is
typical of multipoint buses where cards are attached at
1in or 0.8in intervals along the length of a backplane.
Table 1. Input/Output Function Table
All other combinations of
EN
Flow-Through Pinout
H
EN and EN
ENABLES
L or open
50%
50%
EN
Effect of Capacitive Loading
t
t
PZH
PZL
50%
50%
INPUTS
IN_
H
L
X
V
1.2V
1.2V
V
V
0
V
0
OH
OL
CC
CC
OUT_+
H
Z
L
OUTPUTS
OUT_ -
H
Z
L
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