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LM60: about LM60 behavior at 130degree

Vera Mao
Expert 5065 points
Part Number: LM60
Other Parts Discussed in Thread: TMP235, LMT84

hi dear supporting team,

understand that 130degree is beyond our characterization range, but customer still want to know, if the output voltage at 125degree is 1.205V, when the temp goes to 130degree, will the output voltage be higher?  if yes, is there a estimated  increasing range? tks a lot! 

  • 0
    TI__Guru* 90906 points

    Vera - 

    the average slope is given here for this device at 6.25mV/C + 424mV (see graph on page 1 of the datasheet and average slope in Table 7.5 on page 5 of the datasheet)

    http://www.ti.com/lit/ds/symlink/lm60.pdf

    for example, in the graph:

    At -40C the graph points out the LM60 will have 0.174Vout ...doing the math: (-40 * 6.25mV) + 424mV = 0.174V

    25C the graph points out the LM60 will have 0.580Vout...(25 * 6.25mV) + 424mV = 0.58025V

    125C the graph points out the LM60 will have 1.205Vout...(125 * 6.25mV) + 424mV = 1.20525V

    therefore, the device should have ~1.2365Vout at 130C. 

  • 0 in reply to Josh Wyatt
    TI__Expert 5065 points

    hi Josh,

    tks! so do you mean this chip will still function normally till 130degree? (all the math / precision spec) still works at 130degree?  then what will be the up-limitation of temp for the output voltage stop increase with temp? tks a lot!

  • 0 in reply to Vera Mao
    TI__Guru* 90906 points

    Vera - 

    As you know well I think, in our data sheets on our parts we don't guarantee any accuracy or operation outside of the Absolute Maximum ratings. 

  • 0 in reply to Josh Wyatt
    TI__Expert 5065 points

    hi Josh,

    yes, understand that. so double check with you, below is what we can guarantee:at 130degree, the output voltage will be higher than 125degree. right? 

  • 0 in reply to Vera Mao
    TI__Guru* 90906 points

    Vera -

    Checking internally here with other apps team members to see what has been done above the spec range. Theoretically, you already have the answer. Have you or the customer tried this yourself?

  • 0 in reply to Josh Wyatt
    TI__Expert 5065 points

    Hi Josh,

    thanks for the effort! customer should tried 1pcs chip and find the voltage can go up, but for big volume, if they want to use the function, will still need us provide the guidance. their requirement is if only the output voltage could be increased at 130degree comparing to 125degree, then it is ok. not care much about the precision.  tks a lot!

  • 0 in reply to Vera Mao
    TI__Guru* 90906 points

    Vera - 

    Which package of the LM60 is this customer using at the moment? (LM60 comes in SOT-23 or TO-92 package)

    If they already know they want to go above 125C, what led them to selecting the LM60 over parts like the TMP235, LMT84/85/86/87? 

    Seems logical to me that here you would want to use parts inside their ratings and these other devices seem to do that, and at a lower cost point, if the other parameters they might care about also fit with one of these devices. 

  • 0 in reply to Josh Wyatt
    TI__Expert 5065 points

    HI Josh,

    they are using SOT-23 package. 

    because it is legacy design, they did not predict it could get to such high temp, so they are in evaluating whether need change the solution.

    so have you gotten the answer from internal whether the saying is true: when temp get to 130degree, the output voltage will definitely higher than 125degree?  tks a lot!

  • 0 in reply to Vera Mao
    TI__Mastermind 35855 points

    Hi Vera,

    This product was released in 1996, and we have no additional information from the development. 

    Thanks,

    Ren