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LMK00105: DC coupling connection with other IC

Takashi Imai
Intellectual 410 points

Part Number: LMK00105

Hello,

Could you please help me to ansewr the following question from my customer.

"We are considering to use LMK00105.  As an input connection device for LMK00105, we are considering NB7V52M or NB4L52, but could you tell us if there is an appropriate connection method when connecting with DC coupling? The reason for using DC coupling is to prevent the LMK00105 input from being at an intermediate potential when there is no signal, resulting in noise output.

CML is used when NB7V52M is selected, and with LVPECL when NB4L52 is selected.

The configuration is,
 signal source (differential) - >NB7V52M or NB4L52 (differential) - >LMK00105 (LVCMOS) - > buffer > external. "

Thanks & Regards,
T.Imai

  • 0
    Intellectual 410 points

    Please let me add the customer's expected voltage as below.
    LMK00105:3.3V
    NB7V52M :1.8V
    NB4L52 :3.3V

    The current customer's circuit does not have a 2.5V power supply, so they are intending to use the above power supply.
    If there is any problem with the above power supply configuration, please let me know. The customer is willing to consider changing the power supply.

    Thanks & Regards,
    T.Imai

  • 0 in reply to Takashi Imai
    TI__Genius 17471 points

    Takashi-san,

    When DC coupling, you must simply ensure that the output characteristics of the device before the LMK00105 satisfy the input requirements of the LMK00105, which can be seen below:

    AC coupling would only be required to ensure that the common mode voltage and VIH/VIL levels are satisfied. I suspect there should be no issue with the parts you have listed.

    Thanks,

    Michael

  • 0 in reply to Michael Srinivasan
    Intellectual 410 points

    Hi Michael-san,

    Thank you for your reply.  I would like to inform the customer that the output characteristics of the IC driving the LMK00105 must meet the input requirements of the LMK00105. If the customer has no further questions, I will close this session.

    Thanks & Regards,
    T.Imai