Other Parts Discussed in Thread: LMK05318B
Hello all,
I was just finishing evaluate the LMK05318B when I came across this issue:
I'm using STATUS0 & STATUS1 as an lock detection indicators for ALL2 and DPLL (I use DPLL Mode With Cascaded APLL2)
STATUS0 is set for - DPLL Phase Lock Detection
STATUS1 is set for - PLL2 Digital Lock Detect
Step 1: Both D4 and D5 LEDs are on (indicating both PLLs are locked)
Step 2: I've removed jumper J9 (local XO VCC) to simulate a malfunction and indeed both LEDs turned off.
Step 3: Reinserting J9 brought me back to step 1, as expected.
Step 4: Removing external reference, D4 (DPLL indicator) turned off, and then back on when reconnecting external reference, as expected.
Until now, every indicator is working just fine, until I repeated all steps when the EVM power is off and then turned on:
Step 5: EVM is off, J9 is removed, external reference is on.
Step 6: EVM is turned on, D5 (APLL2 indicator) is ON, when it shouldn't because there is no 48.0048MHz reference presence.
Step 7: Reinserting J9 and D5 remained ON
Step 8: Removing J9 and D5 turned OFF (back to normal operation)
In short, there is a false indication of ALPP2 digital lock detection when powering on the chip with no local reference.
I've found this post, describing almost the same issue, but with a different PLL:
Is there a way to workaround this issue? (I'm not using any system host in my design)
Thanks,
Nir
