5962F9865202VYC View Datasheet(PDF) - Aeroflex UTMC

Part Name

Description

Manufacturer

5962F9865202VYC

Low Voltage Quad Receiver

Aeroflex UTMC 

Receiver Fail-Safe

The UT54LVDS032LV 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 UT54LVDS032LV 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 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 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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