DS90UB936-Q1: IDX

user5782676

Hello,

I have some questions about the IDX of DS90UB936-Q1. If the VDD18=3.3V, RHIGH=10K, RLOW=NC, what the impact of this design is? Will it affect I2C address determination? And what is the probability of chip damage?

In order to eliminate the impact of high voltage, can 1.8V be obtained by adding RLOW to divide the voltage?

Looking forward to your reply. Thanks!

over 2 years ago

0 Vivaan Jaiswal over 2 years ago

TI__Expert 7315 points

Hi,

TI does not recommend exceeding the voltage listed for each pin. Connecting 3.3V to VDD1.8 is not recommended, and may lead the device to perform non-deterministically, and could damage the device.

Regards,

VIvaan

0 user5782676 over 2 years ago in reply to Vivaan Jaiswal

Prodigy 40 points

Hi，

At present, our product has been mass-produced. We have conducted DV and PV tests before, including a 1000 hour durability test, and no issues were found. What is the probability of damage caused by the current design? Can you help analyze the impact from the internal structure of the chip?
Also, are there other ways to reduce risk?

Thanks！

0 Vivaan Jaiswal over 2 years ago in reply to user5782676

TI__Expert 7315 points

Hi,

TI does not recommend using a 3.3V source instead of a 1.8V. The datasheet lays out the following maximum ratings, which includes maximum voltage ratings for the IDX pin. As seen below, the maximum voltage that can be applied is 1.8 + 0.3 = 2.1V. As long as the voltage provided to the IDX pin stays in this range, the implementation should be fine.

Regards,

Vivaan

0 user5782676 over 2 years ago in reply to Vivaan Jaiswal

Prodigy 40 points

Hi Vivaan,

Thank you for your reply. I understand what you mean. We will modify it later, but we need to evaluate the risks of the previous product.
1. Is the internal circuit of IDX pins current type or voltage type? Is the risk of damage much lower after external current limiting through a 10 Kohm resistor?
2. Is the IDX pin protected by a Zener diode? The actual test voltage is approximately 2.4V.

0 Vivaan Jaiswal over 2 years ago in reply to user5782676

TI__Expert 7315 points

Hi,

The IDX Pin is voltage type, and it is not protected by a zener diode. As given above, the pins are limited by the maximum voltage of 2.1V.

Regards,

Vivaan

0 user5782676 over 2 years ago in reply to Vivaan Jaiswal

Prodigy 40 points

Hi Vivaan,

Could you provide the internal circuit of IDX pins?

Thanks.

0 Vivaan Jaiswal over 2 years ago in reply to user5782676

TI__Expert 7315 points

Hi,

Unfortunately, we cannot share internal IC design files in a forum. As iterated above, as long as the voltage on the pin is below the maximum, the device should function optimally. Please let me know if you require assistance with any other questions.

Regards,

Vivaan

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DS90UB936-Q1: IDX