LMK04808: LMK04808 : Design Queries

Nachiketh Karanth

Intellectual 800 points

Part Number: LMK04808

Hi Team,

What will be the output at OSCOUT0/OSCOUT0# if I will be providing 20MHz clock to OSCIN/OSCIN# and single ended 100MHz clock to CLKIN0?
Is there any hardware strap option or software register setting to select the clock reference for OSCOUT0?
If both 20MHz and 100MHz input clocks are present, does it have any auto mode where it selects the reference clock based on internal priority

Thanks

1 month ago

0 Nachiketh Karanth 1 month ago

Intellectual 800 points

Hi Team,

Please provide the updates.

Thanks

0 Michael Srinivasan 1 month ago in reply to Nachiketh Karanth

TI__Genius 12240 points

Hi Nachiketh,

Nachiketh Karanth said:
What will be the output at OSCOUT0/OSCOUT0# if I will be providing 20MHz clock to OSCIN/OSCIN# and single ended 100MHz clock to CLKIN0?

OSCout will buffer out whatever is provided as the reference to PLL2/to OSCin.

Nachiketh Karanth said:
Is there any hardware strap option or software register setting to select the clock reference for OSCOUT0?

The only options are to choose whether to output the OSCin signal or to divide it down further.

Nachiketh Karanth said:
If both 20MHz and 100MHz input clocks are present, does it have any auto mode where it selects the reference clock based on internal priority

Yes. Please see section 8.3.4.3 in the datasheet for more details.

Thanks,

Michael

0 Nachiketh Karanth 1 month ago in reply to Michael Srinivasan

Intellectual 800 points

Hi Michael,

1. Does LMK04808 has non-volatile memory, such that we can store pre-programmed file and it boots during power-up without programming it externally?

2. Will programming effect the output at OSCOUT0 or will it provide output till the time input clock is present at OSCIN regardless of programming?

3. Does LMK04808 have factory pre-programmed variant?

4. Is it possible to get reference clock from CLKIN0 and get it as output from OSCOUT0?

Thanks

0 Michael Srinivasan 1 month ago in reply to Nachiketh Karanth

TI__Genius 12240 points

Hi Nachiketh,

1. No.

2. By default, OSCout will be disabled. You need to program R10 in order to enable OSCout and determine whether the output signal will be divided down or not.

3. No. You can create the desired configuration using TICS Pro, which can be downloaded from https://www.ti.com/tool/TICSPRO-SW

4. No, this is not a feature of this device.

Thanks,

Michael

0 Nachiketh Karanth 1 month ago in reply to Michael Srinivasan

Intellectual 800 points

Hi Michael,

OSCout will be disabled by default at starting of each power cycle and R10 needs to be programmed in order to enable it for each power cycle, am I correct?

Thanks

+1 Michael Srinivasan 1 month ago in reply to Nachiketh Karanth

TI__Genius 12240 points

Hi Nachiketh,

That is correct.

Thanks,

Michael

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LMK04808: LMK04808 : Design Queries