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MSP430G2253 resets when temperature rises above 50C

Phil Maltby
Prodigy 30 points
Other Parts Discussed in Thread: MSP430G2253

We are using the 2253 in an automotive application that is capable of experiencing temperatures in excess of 60C.  When the temperature rises above 50C, the processor resets and continues to do so at approximately 1 second intervals.  Lowering the temperature restores normal operation.  The problem is occurring in multiple units. The 2253 is powered at 3.3V from a TPS7A6633 which is rock steady.  We are using the internal calibrated oscillator; no external crystal involved.  The output pins are connected to high-side drivers and NPN transistors through 4.7K resistors.  One input port is used and isolated through a 47K series resistor fed from a voltage divider (14volts in / 3 volts out).

  • 0
    TI__Mastermind 49692 points

    Hi Phil,

    Thank you for your detailed post.

    This behavior seems strange, especially since you seem to be within the recommended operating temperature (-40C to 85C). Could the part be reaching 85C somehow? Could you try testing this with the MSP430G2253 isolated from all other inputs and outputs (except supply power obviously) to rule out external influences? However, this could be an oscillator fault.

    Since you are using the internal calibrated oscillator, keep in mind that the DCO will change frequency with temperature changes. Since the MSP430G2253 has an internal temperature sensor (not very accurate, used for monitoring the junction temperature), you could change the values of the DCO control registers to keep the DCO frequency in the proper range. This would require calibrated lookup tables covering the expected temperature ranges. Take a look at page 30 in the datasheet for the Calibrated DCO Frequencies and Section 5.2.5.2 Adjusting the DCO Frequency in the User's Guide.

    Regards,

    James

    MSP Customer Applications

  • 0
    Guru 46710 points

    Could be other component like ldo that is causing problems. I would look at the heatedboard using  thermal imager, during 60oC measure supply and reset pin using scope

  • 0 in reply to James Evans
    Prodigy 30 points

    Hi James,

    Thank you for responding to my question.  It turns out the 2253 wasn't resetting; it was actually a spurious interrupt from an external circuit that connects to a blocking diode that under normal circumstances is reversed biased.  The reverse leakage in the diode increases as the temperature rises and eventually raises the voltage on the input above the trigger threshold causing an unwanted interrupt.  So the circuit has been modified to prevent this from happening. Now the unit is actually operating normally at temperatures above 85C.

    Best regards,

    Phil

  • 0 in reply to Phil Maltby
    TI__Mastermind 49692 points
    Hi Phil,

    I'm happy to hear that the issue has been resolved! Thanks for the highly detailed follow-up and solution. I'll go ahead and close the thread.

    Regards,

    James
    MSP Customer Applications

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