We are using MSP430F2617T microcontroller in one of our products. Multiple units from the latest production batch (rev H chips) seem to exhibit a problem where temperature sensor reads incorrect temperature. For example factory calibration data as read from TLV: CAL_ADC_15T30 = 2922 CAL_ADC_15T85 = 3369 The readout from ADC is 3013 counts at room temperature which implies 41C die temperature. I also see slow upward creep in temperature reading. Typically cold unit will start at about 36C and gradually get to 42C. Potential culprit elimination: 1. Is this temperature real? No, does not appear so. I placed a thermocouple on the chip and there was no noticeable temperature rise. Note that on a good unit I see only about 4C between room temperature and die temperature. 2. Firmware bug? Not likely as we have tested and shipped thousands of units with this exact firmware. 3. Known silicon bug? Errata does not have any relevant entries. 4. Assembly error? VCC pins, ground pins, reference pin, crystal pins and reset pin all look good on the scope. Note that ADC is also used for other housekeeping measurements and they all look correct. Not sure what else can affect the internal operation of the chip. Has anybody seen this? Is there a problem with the latest silicon that did not make it into errata? Best Regards, Sergei
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