DS90C402_05 Datasheet, PDF (4/8 Pages) National Semiconductor (TI) – Dual Low Voltage Differential Signaling (LVDS) Receiver

Applications Information (Continued)
1. Open Input Pins. The DS90C402 is a dual receiver
device, and if an application requires only one receiver,
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 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 re-
ceiver 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 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.
Pin Descriptions
Pin No.
2, 6
3, 7
4, 8
5
1
Name
R_OUT
R_IN+
R_IN-
GND
V_CC
Description
Receiver output pin
Positive receiver input pin
Negative receiver input pin
Ground pin
Positive power supply pin,
+5V ± 10%
Ordering Information
Operating
Temperature
−40˚C to +85˚C
Package Type/
Number
SOP/M08A
Order Number
DS90C402M
RECEIVE MODE
R_IN+ − R_IN−
> +100 mV
R_OUT
H
< −100 mV
L
100 mV > & > −100 mV
X
H = Logic High Level
L = Logic Low level
X = Indeterminant State
Note 1: “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the devices
should be operated at these limits. The table of “Electrical Characteristics” specifies conditions of device operation.
Note 2: Current into device pins is defined as positive. Current out of device pins is defined as negative. All voltages are referenced to ground unless otherwise
specified.
Note 3: All typicals are given for: V_CC = +5.0V, T_A = +25˚C.
Note 4: Generator waveform for all tests unless otherwise specified: f = 1 MHz, Z_O = 50Ω, t_r and t_f (0%–100%) ≤ 1 ns for R_IN.
Note 5: Channel-to-Channel Skew is defined as the difference between the propagation delay of one channel and that of the others on the same chip with an event
on the inputs.
Note 6: Chip to Chip Skew is defined as the difference between the minimum and maximum specified differential propagation delays.
Note 7: ESD Rating:
HBM (1.5 kΩ, 100 pF) ≥ 3,500V
EIAJ (0Ω, 200 pF) ≥ 250V
Note 8: Output short circuit current (I_OS) is specified as magnitude only, minus sign indicates direction only. Only one output should be shorted at a time, do not
exceed maximum junction temperature specification.
Note 9: C_L includes probe and jig capacitance.
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