DS90LV032AQML Datasheet, PDF (9/14 Pages) Texas Instruments – DS90LV032AQML 3V LVDS Quad CMOS Differential Line Receiver

(a stable known state of HIGH output voltage) for floating,
terminated or shorted receiver inputs.
1. Open Input Pins. The DS90LV032A is a quad receiver
device, and if an application requires only 1, 2 or 3
receivers, the unused channel(s) inputs should be left
OPEN. Do not tie unused receiver inputs to ground or any
other voltages. The input is biased by internal high value
pull up and pull down resistors to set the output to a HIGH
state. This internal circuitry will guarantee a HIGH, stable
output state for open inputs.
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
resistor 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 balance than flat ribbon
cable.
3. Shorted Inputs. If a fault condition occurs that shorts
the receiver inputs together, thus resulting in a 0V
differential 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
Truth Table
ENABLES
En
En*
L
H
All other combinations of enable inputs
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.
The footprint of the DS90LV032A is the same as the industry
standard 26LS32 Quad Differential (RS-422) Receiver.
Pin Descriptions
Pin No. Name
Description
2, 6,
10, 14
R_I+ Non-inverting receiver input pin
1, 7,
9, 15
R_I− Inverting receiver input pin
3, 5,
11, 13
R_O Receiver output pin
4
En Active high enable pin, OR-ed with En*
12 En* Active low enable pin, OR-ed with En
16
V_CC Power supply pin, +3.3V ± 0.3V
8
Gnd Ground pin
INPUTS
R_I+ − R_I−
X
V_ID ≥ 0.1V
V_ID ≤ −0.1V
Full Fail-safe Open/Short or
Terminated
OUTPUT
R_O
Z
H
L
H
www.ti.com
8