DS90LV048A Datasheet, PDF (6/11 Pages) National Semiconductor (TI) – 3V LVDS Quad CMOS Differential Line Receiver

Applications Information (Continued)
Pin Descriptions
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 resis-
tor across the input pins. The unplugged cable can be-
come 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 balance than flat rib-
bon 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 ex-
ternal 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.
Pin No.
2, 3, 6, 7
1, 4, 5, 8
10, 11, 14,
15
16
9
13
12
Name
R_IN+
R_IN−
R_OUT
EN
EN*
V_CC
GND
Description
Non-inverting receiver input pin
Inverting receiver input pin
Receiver output pin
Receiver enable pin: When EN is
low, the receiver is disabled.
When EN is high and EN* is low
or open, the receiver is enabled.
If both EN and EN* are open
circuit, then the receiver is
disabled.
Receiver enable pin: When EN*
is high, the receiver is disabled.
When EN* is low or open and
EN is high, the receiver is
enabled. If both EN and EN* are
open circuit, then the receiver is
disabled.
Power supply pin, +3.3V ± 0.3V
Ground pin
Ordering Information
Operating
Temperature
−40˚C to +85˚C
−40˚C to +85˚C
Package Type/
Number
SOP/M16A
TSSOP/MTC16
Order Number
DS90LV048ATM
DS90LV048ATMTC
Typical Performance Curves
Output High Voltage vs
Power Supply Voltage
Output Low Voltage vs
Power Supply Voltage
DS100888-12
DS100888-13
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