TRS3232E-Q1: Query Regarding Short-Circuit Protection for TRS3232EQPWRQ1 in ADAS Application

Rajen Mondal

Prodigy 10 points

Part Number: TRS3232E-Q1
Other Parts Discussed in Thread: BZX84C27V-Q1, LM74202-Q1

Tool/software:

hello TI Team,

In one of our ADAS projects, we are using the TRS3232EQPWRQ1 (Automotive grade) to support R323 communication protocol.

I have a few queries regarding protection in case of a short-circuit scenario:

We are considering a test condition where the RIN1 and DOUT1 pins may be exposed to a 32V short-to-battery situation.

Currently, we have placed 499Ω resistors (0402, 0.1%) in series with both RIN1 and DOUT1.
Could you please confirm:

Are these resistors sufficient to protect the IC under a 32V short-to-battery condition?
What would be the expected behavior of the IC if this short occurs?
- Will the internal protection of TRS3232EQPWRQ1 handle this?
- Is there a risk of permanent damage or degradation?
If the resistors are not sufficient, would you recommend adding a series TVS diode at the connector interface?
- If yes, could you suggest suitable TVS diode specifications?

Your guidance will help us ensure robust protection and compliance with automotive standards.

Above the schematic image for your reference.

1 month ago

0 BOBBY 1 month ago

TI__Guru* 75571 points

Rajen Mondal said:
Are these resistors sufficient to protect the IC under a 32V short-to-battery condition?

This protects against an overcurrent scenario but the abs max voltage for the device is still outside the range we spec. The device will still be damaged.

Rajen Mondal said:
What would be the expected behavior of the IC if this short occurs?

Will the internal protection of TRS3232EQPWRQ1 handle this?

Is there a risk of permanent damage or degradation?

Permanent damage will likely occur if the short is sustained.

Rajen Mondal said:
If the resistors are not sufficient, would you recommend adding a series TVS diode at the connector interface?

I think you may need to look at some kind of zener diode since those may be able to handle sustained current but for RS232 you will likely need to also have it bi-directional to ensure it doesn't latch during RS232 operation.

https://www.ti.com/lit/ug/tiduer9/tiduer9.pdf?ts=1753901434560&ref_url=https%253A%252F%252Fwww.google.com%252F

I know the app note above is RS485 but I think the approach could be used for RS232 but you would need to choose a SIDAC that turns on before +/-13V.

-Bobby

0 Rajen Mondal 1 month ago in reply to BOBBY

Prodigy 10 points

hello Bobby,

Thank you for your quick response.

Could you please suggest some part numbers that are automotive-grade and AEC-Q200 qualified?

We are looking for components that meet this standard for use in our current project.

0 BOBBY 1 month ago in reply to Rajen Mondal

TI__Guru* 75571 points

Rajen,

I think I would need to reassign this thread to our protection devices product line to see if they have recommendations.

-Bobby

0 Bryan Rodriguez de San Miguel 1 month ago in reply to Rajen Mondal

TI__Intellectual 1040 points

Hello Rajen!

Our automotive-grade diodes are AEC-Q101, Q100 is regular IC's. AEC-Q200 should not be a deciding factor unless that you are looking for passives. I can also provide some part numbers that are AEC-Q101.

0 Rajen Mondal 1 month ago in reply to Bryan Rodriguez de San Miguel

Prodigy 10 points

Hello Bryan,
could please share the AEC-Q101 part no

0 Bryan Rodriguez de San Miguel 1 month ago in reply to Rajen Mondal

TI__Intellectual 1040 points

Hello Rajen,

Can you provide how long the 32V short-to-battery condition is? This will help me decide what type of diode I should recommend. Is it a prolonged occurrence?

0 Rajen Mondal 1 month ago in reply to Bryan Rodriguez de San Miguel

Prodigy 10 points

Hello Bryan,

32V short-to-battery condition: This is a 1-minute event and not a prolonged occurrence.

Please let me know if any additional protection measures are recommended for this scenario

0 Bryan Rodriguez de San Miguel 1 month ago in reply to Rajen Mondal

TI__Intellectual 1040 points

1 minute is quite long for our diodes. Do you know how much current will be running through the diode? If it is low then our diode might be okay, but it is most likely not low. The best Zener diode we have right now is BZX84C27V-Q1.

Also, here is an App Note on Short to Battery Protection with TI Analog Switches and Multiplexers that can potentially help you as well. Let me know if this helps.

0 Rajen Mondal 1 month ago in reply to Bryan Rodriguez de San Miguel

Prodigy 10 points

hello Brayan,

The BZX84C27V-Q1 Zener diode is not suitable for my RS-232 application. According to the TRS3232EQPWRQ1 datasheet, the pin is rated for a maximum of 13V, and the BZX84C27V-Q1 is not bidirectional also 27V, which is a concern.

For proper protection, we require a bidirectional diode that can safeguard the IC against both positive and negative voltage transients.

Could you please suggest automotive-grade part numbers for the following components?

Bidirectional TVS diode suitable for RS-232 protection (±13V range)
SIDAC (automotive-grade)(±13V range)
PTC (resettable fuse) (automotive-grade)

Your recommendations will help us ensure robust protection in our design.

0 Bryan Rodriguez de San Miguel 1 month ago in reply to Rajen Mondal

TI__Intellectual 1040 points

The ESDS452-Q1 is bidirectional and has a clamping voltage of 8V in a SOT23-3 Package. Additional testing would be required to see if the diode could withstand the duration of the event.

The Protection Devices team does not have SIDAC. I will reassign this thread to the eFuses team to see if they can support with the other request or have a better solution to this.

Hopefully this helps.

0 Rakesh 1 month ago in reply to Bryan Rodriguez de San Miguel

TI__Guru** 106181 points

Team,

We have LM74202-Q1, a 40V device with reverse current blocking and reverse current protection features to provide protection against short-to-battery event.

Please have a look and let us know

BR,

Rakesh

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TRS3232E-Q1: Query Regarding Short-Circuit Protection for TRS3232EQPWRQ1 in ADAS Application