SN74LVC1G04: simple line driver 50R

Pavel Vencalek

Prodigy 90 points

Part Number: SN74LVC1G04
Other Parts Discussed in Thread: SN74LVC1G125, SN74LVC2G125

Hello,

do you have a simple single-ended line driver (50R)?

supply: 3.3V and 5V

delay: say up to 15ns

thank you

over 5 years ago

0 Dylan Hubbard over 5 years ago

TI__Mastermind 42600 points

Hi Pavel,

You can use the SN74LVC1G125 for this application.

0 Pavel Vencalek over 5 years ago in reply to Dylan Hubbard

Prodigy 90 points

Hi Dylan,

I don't think I can. It has too low continuous output current. I might connect say four of them through some resistors (serving also as source termination)

But a single one wouln't make it....

Pavel

0 Emrys Maier over 5 years ago in reply to Pavel Vencalek

TI__Guru* 96591 points

Hi Pavel,

In logic it's far more common to terminate at high impedance (the input to a CMOS device) than it is to terminate with a 50 ohm load. This is quite counter-intuitive for those that are familiar with transmission line theory and deal in RF signals, but it works quite well in most systems. Reflections are reduced through the use of a damping resistor, as described in this application report: Bus-Interface Devices With Output-Damping Resistors or Reduced-Drive Outputs

0 Pavel Vencalek over 5 years ago in reply to Emrys Maier

Prodigy 90 points

Hello Emrys,

I am familiar with the series termination you propose but I have to drive 50R coax, 50R load terminated. It it 3rd party device so I am stucked with that.

I think I will just parallel more LVCs is some manner.....

thank you,

Pavel

0 Dylan Hubbard over 5 years ago in reply to Pavel Vencalek

TI__Mastermind 42600 points

Hi Pavel,

If that's the case you can use the SN74LVC2G125 and parallel the outputs for more drive strength.

Logic

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SN74LVC1G04: simple line driver 50R