Bad SX1250 Clock Signal

While working with the Kompressor v1.0.0 prototype board, I have been noticing a problem with the SX1250 radio failing to go into STANDBY_XOSC mode. Not exactly sure what that means, but it seems to be related to its input clock. So I did some probing with oscilloscope and noticed that the clock signal does not look right.

Here is the relevant schematic. Clock signal comes in from TCXO crystal through series 220 ohm termination resistor and 10pF DC-blocking resistor.

Probe on the SX1250 XTA pin

This is what the clock signal looks like on the SX1250 XTA pin. Two problems here. First, the peak-to-peak is 256mV, well below the 400mV minimum required for this input (See SX1250 datasheet; ATCXO (Amplitude voltage for external TCXO applied to XTA pin). Second, the trace shows a DC offset where there should be none. The series 10pF is a suppose to be a dc-blocking cap. This makes me think a resistor was placed instead of my 10pF cap.

This is likely the reason for STANDBY_XOSC error. This issue is blocking the rest of my board bring up because the SX1250 is suppose to provide the same the clock to the other SX1250 and to the SX1303. Without the clock, it seems the SX1303 stops responding to SPI commands.

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