Hello,
I have a question about the phenomenon of MUXOUT of ADF4117.
The customer's products is in mass production, but there was a AD8342 that did not appear to be normal.
After being powered on, the MUXOUT output high(open) but it goes to low after about 5ms from powered on.
In the thread (ez.analog.com/.../muxout-control-of-adf4117), it said that the MUXOUT is selected 3-THATE OUPUT after POR.
If so, the MUXOUT should output high(open) until configuration via SPI.
Other ADF4117 holds the MUXOUT to high(open) until configuration.
And, the cusotmer select MUXOUT to ANALOG LOCK DETECT but the MUXOUT keeps low(close) after configuration.
Figure 1 is the MUXOUT output of this ADF4117 and Figure 2 is the other's.
This ADF4117 outputs true frequency somewhare in starting up the customer's product.
(The MUXOUT monitor signal is pulled up by the supply of the next circuit. This supply reached 3.3V before starting the 3.3V for ADF4117.)
The question from the customer:
Q1. What is the reason for this phenomenon?
Is a different condition in the start up?
Q2. Can I use this device ongoingly or should it be replaced?
The customer has found this on the device selected to check performance but has not checked all other ADF4117s.
They have not been able to verify if there are other ADF4117s that behave in a similar manner.
Should we simply assume that the MUXOUT of this ADF4117 is faulty?
Best regards,
y_suzuki
