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Original question:

SN74LVTH125: SN74LVTH125 for 1 pulse per second 3.3V LVTTL 50 ohm load drive compatibility

SN74LVTH125: SN74LVTH125 Maximum operating supply current(ICC) during 3.3V LVTTL 50 ohm load drive

Esakki Durai
Prodigy 50 points
Part Number: SN74LVTH125

Tool/software:

Hi Team,

We are planning to use the SN74LVTH125 to drive the 1PPS signal output in our design. As per our design requirement 1PPS signal need to drive 50 Ohms load with <5ns rise time requirements.

So we planned short the four output signal and input signal to share the output load current.

What will be the maximum operating supply current(ICC) during 3.3V LVTTL 50 ohm load drive?

Regards,

Ramesh.

  • 0
    Guru 256060 points

    What is the required voltage at the receiver? When you drive a 50 Ω load with a 50 Ω output impedance, then the two resistors form a divider, and you need twice the voltage at the driver.

  • 0 in reply to Clemens Ladisch
    Prodigy 50 points

    Dear Clemens,

    We need minimum 2.4V at the receiver end. We were planned to reduce output impedance of the buffer by connecting all four outputs in parallel. So that we can get the voltage greater than 1.65V at load end. As per our previous query SN74LVTH125: SN74LVTH125 for 1 pulse per second 3.3V LVTTL 50 ohm load drive compatibility. Refer the attachment for connections.

    Regards,

    Esakki.

    .Buffer connection

  • 0 in reply to Esakki Durai
    Guru 256060 points

    Using CMOS outputs in parallel is allowed. 2.4 V should be possible.

    The supply current is insignificant; VCC must supply only the load current.