INA240: Inquiries regarding INA240 functions

Tanabe Ayato

Part Number: INA240

I am contacting you to inquire about the TI current sense amplifier INA240A2DR.
Please respond to the following questions as soon as possible.

When we conducted a common mode (line vs. FG) lightning surge test on the power supply with the attached current detection circuit, we confirmed that the Vs terminal continued to draw current (about 0.6A).
So, my question is,
- Is there a circuit that continues to flow current to the Vs terminal when an overvoltage (regardless of ±) is applied to any terminal? Please let me know if there is a way to prevent this behavior from continuing.

over 1 year ago

0 Javier Contreras4 over 1 year ago

TI__Mastermind 29650 points

Hello Tanabe,

It sounds like the INA240 got damaged with the test you performed. The reason I say this is 0.6A is too much for the VS pin. Understanding if the current is going through the input pins from VS or is it going directly to GND could point to what got damaged on how to prevent it from failing during your test. During your test what is actually done. By violating absolute max ratings this could damage the part and nothing will work as expected.

Regards,

Javier

0 Tanabe Ayato over 1 year ago in reply to Javier Contreras4

Prodigy 10 points

Dear Javier Contreras4

Thank you for your answer.

I have an additional question.

How large is the parasitic capacitance that occurs between IN(+) and GND and between IN(-) and GND in the INA240's internal circuit?

Thank you for your guidance.

Thank you.

+1 Javier Contreras4 over 1 year ago in reply to Tanabe Ayato

TI__Mastermind 29650 points

Hello Tanabe,

This is typically in the 10pF-20pF range.

Regards,

Javier

0 Tanabe Ayato over 1 year ago in reply to Javier Contreras4

Prodigy 10 points

Dear Javier Contreras4

Thank you for answering.

Let me ask you one more question.

If a voltage is generated in the parasitic capacitance between the input and GND due to the influence of noise, and a minute current flows through the internal circuit, is it possible that the internal circuit behaves like a thyristor?

0 Javier Contreras4 over 1 year ago in reply to Tanabe Ayato

TI__Mastermind 29650 points

Hello Tanabe,

The inputs are connected to an internal ESD protection circuit that is active when it goes the input voltage has a transient that is above the normal operating conditions. Is this what you are seeing? Any inputs that go beyond the input range can trigger this event and if too large could cause damage to the device. Below are the protection we list but the events can be triggered at lower voltages. The capacitance is not from the silicon but more from the connecting bond pads and wire bond parasitics. This would be in the same magnitude of a PCB board.

0 Tanabe Ayato over 1 year ago in reply to Javier Contreras4

Prodigy 10 points

Dear

Mr. Javier

If the ESD protection circuit enters a transient state and continues to be active, the phenomenon is considered to be visible.
Is it possible for you to tell me what kind of structure the ESD protection circuit has? Please let me know if possible.

Thank you.

0 Javier Contreras4 over 1 year ago in reply to Tanabe Ayato

TI__Mastermind 29650 points

Hello Tanabe,

working on this

0 Javier Contreras4 over 1 year ago in reply to Javier Contreras4

TI__Mastermind 29650 points

Hello Tanabe,

We will not share the structure. But this should not remain active if the device is not experiencing a transient that would be considered an ESD event this is normally beyond the Absolute Maximum Ratings for each pin.

0 Tanabe Ayato over 1 year ago in reply to Javier Contreras4

Prodigy 10 points

Dear
Mr.Javier

If an ESD event continues that exceeds the maximum rating for each pin, does that mean the ESD protection circuit will continue to operate?

0 Javier Contreras4 over 1 year ago in reply to Tanabe Ayato

TI__Mastermind 29650 points

Hello Tanabe,

ESD protection is not meant to protect device from continuous exceeding of maximum ratings.

Regards,

Javier

0 Tanabe Ayato over 1 year ago in reply to Javier Contreras4

Prodigy 10 points

Dear

Mr. Javier

Thank you for teaching me about ESD protection circuits.

Let me ask you a few more questions.

Previously, I received the following answer. "But this should not remain active if the device is not experiencing a transient that would be considered an ESD event this is normally beyond the Absolute Maximum Ratings for each pin."

Based on the above, is it possible for the ESD protection circuit to become active even when no transient phenomenon such as ESD occurs?

Or, is it possible for the ESD protection circuit to remain active once a transient occurs?

Sorry for asking you so many questions.

Thank you.

+1 Javier Contreras4 over 1 year ago in reply to Tanabe Ayato

TI__Mastermind 29650 points

Hello Tanabe,

They are designed not to operate in the normal operating conditions of the device. The ESD could get damaged or the part could latch-up when the part is not operating in the range. Latch-up is could happen on the IC other than at the inputs of the device and not the ESD cells. If it returns to normal operation after power cycle if it is Latch-up. If ESD is damaged if would normally not recover and remain damaged.

Regards,

Javier

0 Tanabe Ayato over 1 year ago in reply to Javier Contreras4

Prodigy 10 points

Dear
Mr.Javier

Thank you for your answer.
It's very help full.

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INA240: Inquiries regarding INA240 functions