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CC1120: Problem with CC1120

Part Number: CC1120

Hello

I have a product that contains a CC1120 radio chip.

In some units produced, we have a problem related to the radio operation. In some units that were produced some time ago, and were in storage (With power applied, but in Hibernation, the Radio chip was in Sleep state without activity), when trying to place the units in operation for reconfiguration before sending them to the field we have some units were the radio chip seems to be damaged.

The behavior we are seeing is that we place the "CS" line at '0', and the radio never puts the line "SO" at '0'. Even after a power restart the problem remains. This is what happens in most of the cases, we have one or other case where the radio communicates via SPI, but after we put the radio in Receive mode we never have a valid RSSI value.

Regarding this issue, i would like to have some help from Texas. I have contacted the distributor  where the chips were purchased and he indicated that it was necessary to open a thread in the forum.

Any help would be appreciated.

Thank You

  • The fact that SO never goes low normally indicate that the xtal never starts up.

    Please probe Q1 to see if the xtal is alive or not.
    Please probe the DCOUPL_x pins, RBIAS pin and report the values.

    What is the battery voltage when you wake the unit up?

    "but after we put the radio in Receive mode we never have a valid RSSI value.": Does that mean you never get a RSSI valid?

    Could the unit be exposed to ESD or similar in storage? (If the unit has an external antenna this is exposed)