DS90LV019 Datasheet, PDF (8/10 Pages) National Semiconductor (TI) – 3.3V or 5V LVDS Driver/Receiver

Applications Information (Continued)
• Balanced cables (e.g., twisted pair) are usually better
than unbalanced cables (ribbon cable, simple coax) for
noise reduction and signal quality.
• For cable distances < 0.5m, most cables can be made to
work effectively. For distances 0.5m ≤ d ≤ 10m, CAT 3
(category 3) twisted pair cable works well and is readily
available and relatively inexpensive. For distances
> 10m, and high data rates CAT 5 twisted pair is recom-
mended.
• There are three Fail-Safe scenarios, open input pins,
shorted inputs pins and terminated input pins. The first
case is guaranteed for DS90LV019. A HIGH state on
R_OUT pin can be achieved by using two external resistors
(one to V_CC and one to GND) per Figure 10 (Terminated
Input Fail-Safe Circuit). R1 and R2 should be R_T to limit
the loading to the LVDS driver . R_T is selected to match
the impedance of the cable.
TABLE 1. Functional Table
MODE SELECTED
DRIVER MODE
RECEIVER MODE
TRI-STATE MODE
FULL DUPLEX MODE
DE
RE
H
H
L
L
L
H
H
L
TABLE 2. Transmitter Mode
INPUTS
DE
DI
H
L
H
H
H
2 > & > 0.8
L
X
OUTPUTS
DO+
DO−
L
H
H
L
X
X
Z
Z
X = High or Low logic state
Z = High impedance state
L = Low state
H = High state
TABLE 3. Receiver Mode
INPUTS
RE
(RI+) − (RI−)
L
L (< −100 mV)
L
H (> +100 mV)
L
100 mV > & > −100 mV
H
X
X = High or Low logic state
Z = High impedance state
L = Low state
H = High state
OUTPUT
L
H
X
Z
Pin Name
D_IN
DO±
RI±
R_OUT
RE
DE
GND
V_CC
Pin #
2
11, 12
9, 10
4
8
1
7
14
TABLE 4. Device Pin Description
Input/Output
I
O
I
O
I
I
NA
NA
Description
TTL Driver Input
LVDS Driver Outputs
LVDS Receiver Inputs
TTL Receiver Output
Receiver Enable TTL Input (Active Low)
Driver Enable TTL Input (Active High)
Ground
Power Supply (3.3V ± 0.3V or 5.0V ± 0.5V)
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