Other Parts Discussed in Thread: LMX2594,
Hello,
I have an application using VCO4 at a single clock frequency. We were using the LMX2594, however once the LMX2694-EP became available, we moved to that. I am wondering about the difference between lock detect on the LMX2594 and LMX2694-EP. From the previous post and evaluation of the eval boards, it appears that the LMX2694-EP does not detect a "reference not attached - unlocked condition" on the mux line while the LMX2594 does.
From the previous post it sounds like a Ref IN is required to detect lock effectively on the mux pin in lock detect mode for the LMX2694-EP.
I am also wondering about the best way to utilize the LMX2694-EP for lock detect and its limitations.
It seems like a robust lock detect using no external circuits would be:
- Utilize Vtune and VCOCal on startup over the mux line as "Lock Detect".
- Once the chip has been programed and has had a chance to lock, periodically query R110's rb_LD_VTUNE register for loss of lock in "Readback" mode as part of BIT (built in test) routine
Does this seem reasonable?
