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 100

Ω 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.

Name

Description

2, 6

R

OUT

Receiver output pin

3, 7

R

Positive receiver input pin

4, 8

R

Negative receiver input pin

5

GND

Ground pin

1V

CC

Positive power supply pin,

Ordering Information

Operating

Temperature

Package Type/

Number

Order Number

−40˚C to +85˚C

SOP/M08A

DS90C402M

RECEIVE MODE

R

R

OUT

H

L

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 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 k

Ω, 100 pF) ≥ 3,500V

EIAJ (0

Ω, 200 pF) ≥ 250V

exceed maximum junction temperature specification.

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