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LP2951: Voltage drop due to continuing operation

Guru 11170 points
Part Number: LP2951

Hello E2E,

Our customer is using the LP2951 for mass production product. The output voltage of the LP2951 used in that product had dropped over time.
Initial Voltage : 5.018V
After 4000 hours : 5.007V
Customers want to know the reason for that.
I know that the bandgap Vref has aging characteristics.

Q1
: Does TI have data for internal bandgap aging of LDO?
Q2
: Please let me know why internal bandgap has error by long term aging.

Regards,
ACGUY

  • Hello ACGUY,

    Let me review the archives to see if we have this data.  I will get back to you within 2 business days.

    Thanks,

    - Stephen

  • Hello ACGUY,

    I was not able to locate any long term drift data for this component.  This is a common spec for voltage references but is not a standard industry spec for LDOs. Voltage references are designed, manufactured, and tested to minimize long term drift however this is rarely a key spec for LDOs as long as the output remains within the accuracy spec. That being said it is common for any voltage reference to change during the first few hours that it is powered on. Even for precision voltage references it takes between 100hrs-1000hrs from the first time it is powered for the voltage to settle (see the example plot from a voltage reference below) and an LDO’s internal reference will behave similarly.

    Long term drift is not something that we’ve looked at on many LDO families, so we do not have any data specific to this device. However the one investigation that we’ve done on a different device showed that most of the change in the output voltage occurred in the first ~100 hours or so and resulted in approximately 40mV of change on a 60V output (a 0.67% change).

    To reduce this affect you could run a burn-in on the boards where the boards are operated at high temp to age in the components and help relieve mechanical stresses introduced during the assembly process.  Another option, if this is causing you problems due to a one time calibration for the output voltage, is you may be able to do a calibration more frequently or perform your calibration after the boards have been powered on for some time to allow the majority of the change to take place.

    Thanks,

    - Stephen