SN65DSI84-Q1: Tolerance for I2C pins

Ryuuichi machida

Part Number: SN65DSI84-Q1

Hi,

I would like you to confirm about below.

* When power supply is NOT supplied to SN65DSI84-Q1 but 1.8V signal is applied for I2C pins, is there possiblity that device will receive damage ?

Here is my understanding.

According to dataheet, I understand that there is no possiblity that device will receive damage for "SCL".
1. Absolute voltage is defined fixed voltage (Not related to Vcc)
2. "SCL" has only "I"(CMOS input) function.

However, I'm not sure for SDA.
Because this pin has I/O function and output is defined as "Open-Drain".

So, I would like you to confirm about above.

Best Regards,

over 6 years ago

0 Dennis Wu over 6 years ago

TI__Intellectual 2915 points

Hi,

We are looking into your questions. What is the end application?

Dennis

0 Ryuuichi machida over 6 years ago in reply to Dennis Wu

Guru 11745 points

Hi Dennis-san,

Thank you for your reply.

>What is the end application?

I can not tell you detail on E2E, but I can say this is for Navigation system.

BR,

0 Joel Jimenez0 over 6 years ago in reply to Ryuuichi machida

TI__Mastermind 18655 points

Hello Ryuuichi machida,

SCL and SDA are failsafe which means that these pins will source or sink limited current or no current when chip supply voltage is not applied but voltage is applied on I/O pins.

Based on datasheet, the Absolute maximum Ratings of SCL, SDA and EN should be 2.175 V.

Regards

0 Ryuuichi machida over 6 years ago in reply to Joel Jimenez0

Guru 11745 points

Hi Joel-san,

Thank you for your reply.
>Based on datasheet, the Absolute maximum Ratings of SCL, SDA and EN should be 2.175 V.
I want to confirm one more.

Is there any restriction for current ?
In case of "EN", there is possiblity that less than 2mA will flow to this pin.

Best Regards,

0 Joel Jimenez0 over 6 years ago in reply to Ryuuichi machida

TI__Mastermind 18655 points

Hello Ryuuichi,
It supports up to 30 μA
Regards

0 Ryuuichi machida over 6 years ago in reply to Joel Jimenez0

Guru 11745 points

Hello Joel-san,

Thank you for your reply.

>It supports up to 30 μA
I guess that this is quoted from "Input failsafe leakage current"

I recognize this is just leakage current when Vcc = 0V with Vcc(pin) = 1.8V.

What I want to confirm is that tolerance of input current which device will not receive damage when Vcc = 0V with Vcc(pin) = 1.8V.

If my guess is not correct, please correct me.

Best Regards,

0 Joel Jimenez0 over 6 years ago in reply to Ryuuichi machida

TI__Mastermind 18655 points

Hello machida-san,

Your stament is correct.

Regards

0 Ryuuichi machida over 6 years ago in reply to Joel Jimenez0

Guru 11745 points

Hi Joel-san,

Thank you for your confirmation.

Do you have answer for below ?

>What I want to confirm is that tolerance of input current which device will not receive damage when Vcc = 0V with Vcc(pin) = 1.8V.

"30uA" is just leakage current. so i would like you to confirm about above as well.

BR,

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SN65DSI84-Q1: Tolerance for I2C pins