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AWR1843: POH

Notozman
Expert 7536 points
Part Number: AWR1843
Other Parts Discussed in Thread: AWR2944,

Hi Team, 

2 questions on POH, 

1) for the AWR2944 and AWR1843 we publish a use-case profile for temperature/time in the datasheets, but I dont see a lifetime PoH for max Tj quoted. Do we have this number as well ? For example at Tj = 105degC, 125degC ? 

2) for AWR1843, why is the duty cycle set to 100% when we normally quote 50% max ? 

Thanks. 

  • 0
    TI__Mastermind 30545 points

    Hello,

    The POH in the datasheet assumes a 9% operation time at 125C junction, which is the max junction temperature of the device. We do not spec a value for running at 125C junction for the entire life of the sensor. That is not a typical use case and we do not expect sensors to be running their entire life at the maximum junction temperature. The temperature profile is based around a typical automotive use case.

    Yes, it is strange that it is specified at 100% duty cycle. If you look at newer devices such as AWR2944, the spec is for 50% duty cycle. However, the important spec is the junction temp. If you are operating at 50% duty cycle with the same temperature profile as specified in the datasheet, the POH would remain the same. 

    Regards,

    Adrian

  • 0 in reply to aozer
    TI__Expert 7536 points

    Thanks Adrian, 

    Is there a reason 9% is chosen for Tj = 125degC ? Why that particular number as well as the other %'s used in the table ? 

    For the duty cycle - also older devices seem to be quoted @ 50% as well - do you have a 50% POH number for the 1843 as well ? 

    Thanks !

  • 0 in reply to Notozman
    TI__Mastermind 30545 points

    Hello,

    We do not have 50% data, but this should not really matter. The life is depended on junction temperature, not duty cycle. So, if you are operating at these same temperatures with a 50% DC instead of 100% DC, the POH specs would not change.

    As part of the AEC qualification, we do HTOL stress testing which is where these specs would be derived from.

    https://www.ti.com/qualificationsummary/qualsumm/home?actionId=2800 

    Regards,

    Adrian

  • 0 in reply to aozer
    TI__Mastermind 30545 points

    Hello,

    I discussed this further with our analog designer and my statement above was not correct. The duty cycle will have a direct impact on POH, even if temperature is the same for both cases.

    At 50% duty cycle you can double the POH from the 100% duty cycle case, so this would equate to roughly 20k hours at 50% duty cycle for the temperature profile given in the datasheet.

    Regards,

    Adrian

  • 0 in reply to aozer
    TI__Expert 7536 points

    Thanks Adrian.