LMK05028EVM: The .TCS files you provided me did not work

user4779049

Part Number: LMK05028EVM
Other Parts Discussed in Thread: LMK05028

Kia-san,

Please advise on my questions bellow.

Q1. There are two check marks in Validation timer box (left and right of IN0) on TICSPRO GUI,
how they affect to the results?

Q2. There is Trefvalid parameter (.01s to 12.8 s) , how does it influence to the results.

Q3. When the reference frequency is as low as 67 kHz, without turning of the validation timer
(instead of Frequency Detect threshold check box) DPLL did not locked.
Why this occurs?
How much the frequency is classified as Low frequency?

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The .tcs files you provided me did not work.

The LEDs for Status 0 and Status 1 kept on, and the output clock moved against the reference clock

despite of issuing Soft-Reset.

However, when I tried turning off the Validation timer check box, the LEDs for Status 0 and Status 1 turned off, and

output clock stayed against the reference clock

This case, despite of turning on the Frequency detect threshold check box, the DPPL got locked.

I am not fully confident that this action is appropriate and robust workaround for the No Lock issue,

and want to know more about the reference validity check mechanism.

Are there any document which describes the detail mechanism of the reference validity check?

Mita

over 3 years ago

+1 Kia Rahbar over 3 years ago

TI__Expert 8585 points

Hello Mita,

1. The check box highlighted in yellow signifies that IN0 is being used. The check box circled in blue enables the validation timer. The validation timer is used to set the amount of time the device waits before it starts trying to validate the reference. The check box circled in black enables the frequency detect threshold. The frequency detect threshold is used to set the ppm range in which the device will consider the reference valid. All three of these should be enabled.

2. The Trefvalid determines the amount of time the device waits before it starts trying to validate the reference.

3. The validation timer check boxes (both the check box highlighted in yellow and check box circled in blue) both need to be enabled always. If these are disabled, it will consider any reference as valid, so it will not be an accurate state of your DPLL.

The LMK05028 can accept any frequency between 5 MHz and 750 MHz for a differential input. The LMK05028 can accept any frequency between 1 Hz and 250 MHz for a single-ended input.

Section 9.3.8.3 Reference Input Monitoring in the data sheet (pages 36 -38) provides an explanation on all the reference monitors. Here are snippets of those sections: