DRV8870: Absolute Maximum Ratings OUT1 and OUT2

Yusuke Mukuno

Part Number: DRV8870

In generally, we have not to exceed the absolute maximum rating even if a moment.

But, I want to exactly confirm about DRV8870 OUT1 and OUT2 pins Absolute Maximum Ratings.

OUT1 and OUT2 pins will drop to negative voltage between dead time. (dead time = 220ns typ, Actually, it is exceed it at the waveform of Figure 11 (around -2V).)

And, the datasheet is written "Continuous". So, I think, it is rating in the case of apply continuous voltage.

My understanding is below,

The negative voltage during tDEAD is not covered by the absolute maximum ratings, because the negative voltage during dead time is an internal behavior, it isn't an external stress.

Is it correct?

If it is not correct, Could you please let me know the definition of "Continuous"? (over xxx ms is NG, something like that )

Absolute maximum rating

Continuous phase node pin voltage (OUT1, OUT2) : -0.7 to VM+0.7

Footnote (1)

(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

Muk

over 5 years ago

0 Hector Hernandez Luque over 5 years ago

TI__Expert 8985 points

Hi Mukuno-san,

Let me ask a question before providing answers:

The customer is seeing -2V for a duration less than the dead time, 220ns, and it occurs during the dead time, correct? If so, how long is it -2V?

0 Yusuke Mukuno over 5 years ago in reply to Hector Hernandez Luque

TI__Expert 7395 points

Regarding my description of -2V,

It is shown in figure 11 of the datasheet (example) . Actually, it is between -1V and -2V.

Muk

0 Hector Hernandez Luque over 5 years ago in reply to Yusuke Mukuno

TI__Expert 8985 points

Hi Mukuno-san,

I am checking internally. I expect to have a response before the end of the week, CDT.

0 Hector Hernandez Luque over 5 years ago in reply to Hector Hernandez Luque

TI__Expert 8985 points

Hi Mukuno-san,

What is the current on OUTx in this condition?

0 Yusuke Mukuno over 5 years ago in reply to Hector Hernandez Luque

TI__Expert 7395 points

Hi Hector-san,

I don't know the current condition at this waveform (figure 11).

Customer mentioned, especially, this concern is occurred when OUTx is High-Z.

However, as you know, my question is regarding the definition of absolute maximum rating for voltage.

Muk

0 Hector Hernandez Luque over 5 years ago in reply to Yusuke Mukuno

TI__Expert 8985 points

Hi Mukuno-san,

Ok, I understand it is all from datasheet scope capture now. I am checking this information internally and I will get back to you by EOD Monday or sooner., CDT.

0 Hector Hernandez Luque over 5 years ago in reply to Hector Hernandez Luque

TI__Expert 8985 points

Hi Mukuno-san,

The OUTx voltage depends on the current flowing through the low-side FET body diode during dead time.

If the current is low, we see the body diode voltage at -0.7V (OUTx abs min value).

If the current is high, the drop across the body diode will be higher.

To my understanding, we should not be violating any abs min at any moment.

I am still investigating if it the abs min of -0.7V is valid during the dead time.

Expect a response by EOD Tuesday CDT.

0 Yusuke Mukuno over 5 years ago in reply to Hector Hernandez Luque

TI__Expert 7395 points

Hernandez-san

Thank you for your support.

Do you have any update?

Muk

0 Hector Hernandez Luque over 5 years ago in reply to Yusuke Mukuno

TI__Expert 8985 points

Hi Mukuno-san,

We are still confirming internally. I expect a response by EOD Wednesday, CDT.

0 Hector Hernandez Luque over 5 years ago in reply to Hector Hernandez Luque

TI__Expert 8985 points

Hi Mukuno-san,

The scope capture in Figure 11 was not taken with a differential probe and was not measured at the pins. The intent of the scope capture was to show prop delay variation, not negative voltage transients. The images are not representative of the voltage at the pins of the device.

0 Yusuke Mukuno over 5 years ago in reply to Hector Hernandez Luque

TI__Expert 7395 points

Hi Hernandez-san

Thank you for your answer.

Muk

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DRV8870: Absolute Maximum Ratings OUT1 and OUT2