LM258 output short circuit

K.Hamamoto

Other Parts Discussed in Thread: LM258

I have some question about LM258. On the datasheet, the duration of output short circuit to ground is defined as the following image.

I do not understand that "Unlimited" means.

>> Is there any possibility to cause excessive heating and eventual destruction same as short circuits from outputs to VCC?

>> Is there any protection(OCP?) to prevent that heating and eventual destruction when the output is shorted to ground?

>> For short from output to Vcc, it can be caused excessive heating and eventual destruction.

What kind of destruction will be happen?

Regards,

Koji Hamamoto

over 9 years ago

0 Ron Michallick over 9 years ago

TI__Guru**** 166746 points

Koji san,

Current is limited and regulated with a short to ground. When Ta is <=25C and VCC is <=15V then the device will survive.

For short to VCC, there a PNP follower that does not have a current limit. Therefore damage may occur, probably in the form of a short to ground on output.

0 K.Hamamoto over 9 years ago in reply to Ron Michallick

Guru 12155 points

Hi
Thank you for your reply.

As you mentioned , the short current is limited when it short from output to GND.
(short circuit output current ; +/-60mA max)

So it is no limitation of short time for the duration of output short circuit to ground.
(Ta <= 25degC and VCC <=15V)

Is my understanding correct?

Regards,
Koji Hamamoto

0 Ron Michallick over 9 years ago in reply to K.Hamamoto

TI__Guru**** 166746 points

Koji san,

Yes you are correct

0 K.Hamamoto over 9 years ago in reply to Ron Michallick

Guru 12155 points

Hi Ronald-san

Thank you very much for your support.

It is protected by current limit when the VCC is <=15V. However what happen to this device when VCC is >15V?

Regards,
Koji Hamamoto

0 K.Hamamoto over 9 years ago in reply to K.Hamamoto

Guru 12155 points

Could you give me any advice about the above question?

Regards,

Koji Hamamoto

0 Ron Michallick over 9 years ago in reply to K.Hamamoto

TI__Guru**** 166746 points

Koji san,

The sourcing current limit works at all VCC values.
When VCC > 15V there is greater chance that internal heating will be too high.

Heating due to output sourcing current is TJA * (VCC - VOUT) * IOUT

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LM258 output short circuit