LM79L12 - operation under less than 0 degree

Hirotaka Matsumoto

Hi all,

Would you mind if we ask LM79L12?

We know that Operating Temperature Range of LM79L12 is from 0 degree to 70 degree.
If we use it under less than 0 degree(like as -5degree), what problems does it occur?
Increasing of ripple, no stability etc,

Of cource, in order to convince our customer not to use except Operating Temperature Range
we use this information.

Kind regards,

Hirotaka Matsumoto

over 10 years ago

0 Tim Reyes over 10 years ago

TI__Expert 3920 points

Hi Matsumoto-san,

The Typical Performance Characteristics section shows the performance you can typically expect from Tj = 0 to 125C. Even though Ta may be slightly below 0C, it is possible that Tj is within 0 to 125C range, depending on the power you are dissipating.

Tim

0 Hirotaka Matsumoto over 10 years ago in reply to Tim Reyes

Guru 27585 points

Tim san,

Thank you for your update.

Ta may be slightly below -5C, Tj will be less than 0C(-2C or -3C?).

We'd like to confirm that if the device is used in case of less than 0C(-5C),
you can't imagine what will be happend, right?

Otherwise, in conclusion you can't insure the performance Characteristics, right?
And then, may it be occurred following problems?
-It starts to oscillate,
-It increased ripple voltage,

Kind regards,

Hirotaka Matsumoto

0 Tim Reyes over 10 years ago in reply to Hirotaka Matsumoto

TI__Expert 3920 points

Unfotunately, I haven't tried this. If Tj is less than 0C, then you are operating the part outside its intended operating range. although it may still function, I can't guarantee it.

0 Hirotaka Matsumoto over 10 years ago in reply to Tim Reyes

Guru 27585 points

TIm san,

Thank you for your update!
Ok, we got it.

Kind regard,

Hirotaka Matsumoto

Power management

Power management forum

LM79L12 - operation under less than 0 degree