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LMK00804B-Q1: LMK00804B-Q1 Termination

Renan Santos Adriano
Mastermind 22280 points
Part Number: LMK00804B-Q1

Dear Team,

My Customer would like to ask if Is it possible to terminate this part LMK00804B-Q1 with a 50ohm to ground (see attached diagram)?

Your inputs is highly appreciated.

Best regards,

Renan

  • 0
    TI__Genius 12705 points

    Hello,

    Generally we would not recommend such a low impedance path to GND as it may affect the output driver.

    Is there a reason they prefer not to use a series resistor as recommended?

    Regards,

  • 0 in reply to Liam Keese
    Prodigy 30 points

    Our load requires to have 50ohm termination.

    Is the concern power consumption or the peak current is outside the driver specs?

    Our operating conditions are low duty cycle 1%  20ns pulse and 200ns period.

  • 0 in reply to Lucas Morales
    Prodigy 30 points

    Typo

    Our operating conditions are low duty cycle 1%  20ns pulse and 2000ns period.

  • 0 in reply to Lucas Morales
    TI__Genius 16845 points

    Hi Lucas,

    LMK00804B-Q1 can drive 50-ohm loads. As Liam mentioned, it is recommended to route the clock outputs with Rs = 43ohms for impedance matching for best signal integrity.

    Kind regards,
    Lane

  • 0 in reply to Lane Boyd
    Prodigy 30 points

    Hi,

    Please clarify:

    Understand the Rs=43ohm is recommended.

    My question was for termination with  50 ohms to ground.

    "Generally we would not recommend such a low impedance path to GND as it may affect the output driver"

    Our load requires to have 50ohm termination to ground.

    Is the concern power consumption or the peak current is outside the driver specs?

    Our operating conditions are low duty cycle 1%  20ns pulse and 2000ns period.

    Would operating with 50 ohm to ground be reliability issue?

     

  • 0 in reply to Lucas Morales
    TI__Genius 16845 points

    Hi Lucas,

    No, 50ohms to GND is not a reliability issue, it is related to power consumption and current as you indicated. It is generally not recommended because 50ohm termination is a heavy load for LVCMOS drivers which expect to drive high impedance loads. However, you can see that some of the electrical characteristics are specified for a 50ohm load to VDD/2.

    Kind regards,
    Lane