OPA2990: About Powerup sequence

Hide

Guru 21045 points

Part Number: OPA2990

Hi Team,

I would like to use OPA2990S the following powerup sequence.

1. V- = -15V (VS= -15V)

2. V+ = +15V (VS=30V)

According to datasheet, absolute Maximum Ratings of “VS = (V+) – (V–)” is 0V to 42V.

Can I apply "V-" first?

And, could you please let us know a recommended powerup sequence?

(Timing of apply of V+ and V- etc.)

Regards,

Hide

over 4 years ago

0 kai klaas69 over 4 years ago

Guru 140200 points

Hi Hide,

correct me if I'm wrong, but 30V - (-15V) = 45V is beyond the maxium rating of supply voltage of OPA2990 :-)

Kai

0 Tim Claycomb over 4 years ago

TI__Genius 15410 points

Hi Hide,

It is not recommended to operate at the absolute maximum supply. You should always stay at or below the recommended operating conditions. Absolute maximum ratings are limits where damage may occur when exceeded.

When V- turns on first Vs = 0V - (-15V) = 15V so you would not be violating the absolute maximum conditions. Then when V+ turns on Vs = 15V - (-15) = 30V.

There is not a recommended power up sequence but the power supplies should turn on together as close as possible. I do not see an issue with turning on V- first, this will provide a return current path before the op amp turn on. I recommend watching our TI Precision Lab videos on EOS for more information. There is information in the videos about power up sequencing and protecting the device.

Thank you,

Tim Claycomb

0 Former Member over 4 years ago

Hello Hide-san,

To learn more about this subject, I recommend you see the videos linked by Tim above. However, the most relevant portion of the presentation is slides 7 and 8 from video/presentation 12.1 TI Precision Labs - Op Amps: Electrical Overstress - Introduction.

Regards,
Daniel

0 Hide over 4 years ago in reply to Former Member

Guru 21045 points

Hi Tim-san, Daniel-san,

Thank you for the information.

I greatly appreciate your cooperation.

Regards,

Hide

0 kai klaas69 over 4 years ago in reply to Hide

Guru 140200 points

Hi Hide,

and don't fall into this latch-up trap:

Kai

0 Hide over 4 years ago in reply to kai klaas69

Guru 21045 points

Hi Kai-san,

Thank you for the information.

Regards,

Hide

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