DS90LV031B_05 Datasheet, PDF (7/9 Pages) National Semiconductor (TI) – 3V LVDS Quad CMOS Differential Line Driver

Applications Information (Continued)
2. Terminated Input. If the driver is disconnected (cable
unplugged), or if the driver is in a TRI-STATE or power-
off condition, the receiver output will again be in a HIGH
state, even with the end of cable 100Ω termination re-
sistor across the input pins. The unplugged cable can
become a floating antenna which can pick up noise. If
the cable picks up more than 10mV of differential noise,
the receiver may see the noise as a valid signal and
switch. To insure that any noise is seen as common-
mode and not differential, a balanced interconnect
should be used. Twisted pair cable will offer better bal-
ance than flat ribbon cable.
3. Shorted Inputs. If a fault condition occurs that shorts
the receiver inputs together, thus resulting in a 0V differ-
ential input voltage, the receiver output will remain in a
HIGH state. Shorted input fail-safe is not supported
across the common-mode range of the device (GND to
2.4V). It is only supported with inputs shorted and no
external common-mode voltage applied.
External lower value pull up and pull down resistors (for a
stronger bias) may be used to boost fail-safe in the presence
of higher noise levels. The pull up and pull down resistors
should be in the 5kΩ to 15kΩ range to minimize loading and
waveform distortion to the driver. The common-mode bias
point should be set to approximately 1.2V (less than 1.75V)
to be compatible with the internal circuitry.
FIGURE 7. Driver Output Levels
Pin Descriptions
Pin No.
1, 7, 9, 15
2, 6, 10, 14
3, 5, 11, 13
4
12
16
8
Name
Description
D_IN Driver input pin, TTL/CMOS
compatible
D_OUT+ Non-inverting driver output pin,
LVDS levels
D_OUT− Inverting driver output pin, LVDS
levels
EN Active high enable pin, OR-ed
with EN*
EN* Active low enable pin, OR-ed with
EN
V_CC Power supply pin, +3.3V ± 0.3V
GND Ground pin
Ordering Information
Operating
Temperature
−40˚C to +85˚C
Package Type/
Number
SOP/M16A
Order Number
DS90LV031BTM
7
10131109
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