5962G9583401QXC View Datasheet(PDF) - Aeroflex Corporation

Part Name

Description

Manufacturer

5962G9583401QXC

Quad Receiver

Aeroflex Corporation 

Receiver Fail-Safe

The UT54LVDS032 receiver is a high gain, high speed device

that amplifies a small differential signal (20mV) to TTL logic

levels. Due to the high gain and tight threshold of the receiver,

care should be taken to prevent noise from appearing as a valid

signal.

The receiver’s internal fail-safe circuitry is designed to source/

sink a small amount of current, providing fail-safe protection (a

stable known state of HIGH output voltage) for floating,

terminated or shorted receiver inputs.

1. Open Input Pins. The UT54LVDS032 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 three-state 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 offers 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 remains in

a HIGH state. Shorted input fail-safe is not supported

across the common-mode range of the device (VSS to

2.4V). It is only supported with inputs shorted and no

external common-mode voltage applied.

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