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LMH1983: Power consumption optimization

Prodigy 90 points

Replies: 6

Views: 239

Part Number: LMH1983

Hello, We are using the LMH1983 in an application where power consumption is critical.

As we need only PLL1 I am applying the next register configuration

Registers 0x2E, 0x31 and 0x34 = 0x08 

Register 0x05  = 0x29

The rest of the registers has the default configuration.

¿Is this the best configuration to reduce the power consumption using PLL1 or does any other register configuration reduce even more the power consumption?

in some cases, we also need to powerdown the LMH1983. For that I am using the next register configuration.

Registers 0x2E, 0x31 and 0x34 = 0x08 

Register 0x05  = 0x40

Same question ¿Is this the best configuration to powerdown the LMH1983?

Thank you very much for your support.

Regards

  • Hi Marcos,

     please expect a feedback early next week.

    Regards,

    Hao

  • In reply to Hao Z:

    Hi Marcos,

     I'll try to help. This thread talks about powerdown bit: https://e2e.ti.com/support/interface/f/138/t/707816?tisearch=e2e-sitesearch&keymatch=LMH1983%25252525252520power

    I can't put the full register map here but I may be able to provide more information on certain registers. 

    Regards,

    Hao

  • In reply to Hao Z:

    Hello Hao,

    Thanks for your reply. I already read that thread before.

    I understand that you can't put the full register configuration here but based in my first post, could we do anything else to reduce even more the power consumption?

    Best regards,

    Marcos

  • In reply to Marcos Garcia:

    Hello Marcos,

    It seems you are already powering down PLL2, 3 and 4 which is recommended to reduce current.

    For power down bit set, 0x04[6] = 1, provides low current standby setting. For lower current you can disable the 3.3V supply input to shutdown the LMH1983.

    There is some dependence of current on the output swing and loading capacitance in normal operation. You can adjust the swing in register 0x3A.

    Regards,

    Liam

    Liam Keese

    Clock and Timing Systems & Applications


    To design your own Clock Tree solution, visit WEBENCH Clock Architect ​​​​

    More information Clock and Timing System products: http://www.ti.com/clock-and-timing/overview.html

  • In reply to Liam Keese:

    Hi Liam, 

    For power down I guess that you mean bit 0x05[6] because 0x04[6] is reserved. We are already doing this.

    We will try to change the output swing to see if that reduces the power consumption.

    Thanks and regards,

    Marcos

  • In reply to Marcos Garcia:

    Hello Marcos,

    Yes, 0x05[6]  is correct.  I hope the output swing can reduce the power to meet your needs.

    Regards,

    Liam

    Liam Keese

    Clock and Timing Systems & Applications


    To design your own Clock Tree solution, visit WEBENCH Clock Architect ​​​​

    More information Clock and Timing System products: http://www.ti.com/clock-and-timing/overview.html

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