LMH1983: Power consumption optimization

Marcos Garcia

Prodigy 110 points

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

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

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

Thank you very much for your support.

Regards

over 6 years ago

0 Hao Z over 6 years ago

TI__Mastermind 18070 points

Hi Marcos,

please expect a feedback early next week.

Regards,

Hao

0 Hao Z over 6 years ago in reply to Hao Z

TI__Mastermind 18070 points

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%25252525252520powe r

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

Regards,

Hao

0 Marcos Garcia over 5 years ago in reply to Hao Z

Prodigy 110 points

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

0 Liam Keese over 5 years ago in reply to Marcos Garcia

TI__Genius 12705 points

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

0 Marcos Garcia over 5 years ago in reply to Liam Keese

Prodigy 110 points

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

0 Liam Keese over 5 years ago in reply to Marcos Garcia

TI__Genius 12705 points

Hello Marcos,

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

Regards,

Liam

Clock & timing

Clock & timing forum

LMH1983: Power consumption optimization