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CC2640R2F-Q1: Time from reset pin pulling up to crystal oscillator starting

HY yang
Expert 1980 points
Part Number: CC2640R2F-Q1

Our customers use cc2640r2ftwrgzrq1 to produce a car key. Abnormal products of 1pcs were found in the 9000pcs products recently produced. The normal IC starts to vibrate after the reset pin is pulled up for 37.2ms. The abnormal IC starts to vibrate after the reset pin is pulled up for 167.5ms, and the reset pin has already appeared the falling edge. The test picture we provide is shown in the figure below. The Crystal Pin refers to pin46 and pin47. Does the crystal oscillator start up after the reset pin is pulled up for 167.5ms meet the normal operating parameter range of cc2640r2f-q1?

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    TI__Guru**** 169174 points

    Hi,

    HY yang said:
    Does the crystal oscillator start up after the reset pin is pulled up for 167.5ms meet the normal operating parameter range of cc2640r2f-q1?

    No. The startup time is shown in section 8.8 and 8.9 of the device's datasheet.

    What pin in the IC the green trace is measuring? Is it a specific I/O pin or are you measuring overall power consumption, etc?

    The reason of my question is that, if the device is only able to show activity on the I/O pin after a very long time, it might be something during its own initialization - either insufficient power (I would monitor power rails as well) or even software. The device itself starts up after only about 150µs, so the timings you are getting are much longer than that.

    Keep in mind that, if you are trying to measure the XTAL pin itself, the oscilloscope probe will add extra load to the crystal and the oscillations might not start.

    Hope this helps,

    Rafael