• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 48 subscribers
  • Views 837 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LMV7219: Operating Supply Voltage and its Effect on Part Life

Jeff Schwartz
Prodigy 30 points
Part Number: LMV7219

LMV7119

For this device, I need help in calculating the decrease in the life of this part if the operating supply voltage is close to its maximum allowable operating voltage.  We have a supply voltage derating of 80%. So, the derated supply voltage is 4.4V (80% of 5.5V rated) but the operating supply voltage is 5.0V. Is there a formula that I can use ? Is there some other way to calculate the life? Does the part run hotter at higher supply voltages?  If so, can that be calculated?

Thanks,

Jef

  • 0
    TI__Mastermind 24260 points

    Jeff

    Sorry this is taking longer than usual to get back to you.

    From the product folder I went to the quality tab where we publish information regarding lifetime.  Unfortunately, there is no formula or specified operating mentioned.  With that said, our products are designed to have no significant lifetime reduction while operating within the recommended operating conditions.  This includes the boundary which in the case of the LMV7219 is 5V.  there is very minimal change in quiescent current from min operating voltage to max, so there would be little to indicate any reduction related to operation voltage in the recommended range.

    www.ti.com/.../estimator.tsp

  • 0 in reply to Chuck Sins
    Prodigy 30 points
    I ask some question to Sean Rauchfuss, TI Technical Sales Representative, over the phone and I summarized my questions in an email to him. Sean is out of the office and wont return until 4/24 but I am looking for answers to my question ASAP.
    This is the email I sent to Sean:

    Hi Sean,

    Thank you for our telephone conversation from today concerning the derating of the subject device.

    As you requested, here is my outline of the derating issues.

    Generally, I need clarification of Note 4 from the Absolute Maximum Ratings section of the LMV7219 Comparator and I also need to find out what the impact of the part’s useful life is when operating the part above its rated value.

    Specifically:

    a) For part #1, the Vin+ is 5.826 V, the rated Vin+ is 5.4 V, the derated Vin+ is 3.78 V (70% of 5.4 V).
    b) For part #2, the Vin+ is 6.251 V, the rated Vin+ is 5.4 V, the derated Vin+ is 3.78 V (70% of 5.4 V).

    Please provide clarification of Note 4 from the data sheet that says, “Limiting input pin current is only necessary for input voltages that exceed maximum input voltage ratings.”

    The suggestion is to use a resistive divider to meet the 70% input voltage derating factor (Vin / VinMax). Note that it is possible for the series input resistor to form a divider with the device input stage constant current. In this case, the voltage at the input terminals can be below the derating factor.

    What criteria is used to select the series resistor and what resistance value is recommended?

    How is the resistance value calculated?

    Also, what is the impact of the part’s useful life is when operating the part above its rated value as shown in a) and b) above. How much is the useful life degraded? How is that calculated?

    Thank You,
    Jeff Schwartz
  • 0 in reply to Jeff Schwartz
    TI__Guru 52486 points
    This is being handled via internal email.