TCA9803: About VIH

kakeru manita

Prodigy 50 points

Part Number: TCA9803

Hi team,

Table 7.2 states that the VIH MAX is VCCA/VCCB, but should it not exceed VCCA/VCCB at all?

Best Regards,

8 months ago

0 Clemens Ladisch 8 months ago

Guru 290750 points

The absolute maximum ratings allow up to 4 V. So the device will not be damaged, but with I²C voltages above VCCx, correct operation is no longer guaranteed.

0 Tyler Townsend 8 months ago

TI__Mastermind 34893 points

Hi Kakeru,

Like CLemens has stated, a VIH above VCCx will no longer guarantee correct operation of the device since this was not tested during the validation of the device.

Regards,

Tyler

0 kakeru manita 8 months ago

Prodigy 50 points

Thank you for answering,Clemens ＆ Ttyler

If overshoot occurs, it will exceed VCCx, but does this mean that operation is not guaranteed?

Best Regards,

0 Clemens Ladisch 8 months ago in reply to kakeru manita

Guru 290750 points

I²C uses pull-up resistors (or a current source on the TCA980x's B side), so overshoots should not be a concern.

0 Tyler Townsend 8 months ago in reply to kakeru manita

TI__Mastermind 34893 points

Kakeru,

The device is not guaranteed by the datasheet if the recommended operating conditions are out of spec.

The device will most likely operate correctly in your design, but from a datasheet perspective, we can't guarantee electrical functionality or electrical characteristics of the device.

Regards,

Tyler

0 kakeru manita 8 months ago in reply to Clemens Ladisch

Prodigy 50 points

Clemens,
Isn't overshoot occurring due to signal reflection due to impedance mismatch?
Regards,

+1 Clemens Ladisch 8 months ago in reply to kakeru manita

Guru 290750 points

I²C rising edges are not fast enough for that.

In any case, I have not heard from any such problems in practice.

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TCA9803: About VIH