PCA9538: does this part support schmitt trigger

user4979989

Intellectual 2800 points

Part Number: PCA9538

Hi team,

May I know does PCA9538 support schmitt trigger?

Thank you.

over 4 years ago

0 BOBBY over 4 years ago

TI__Guru 72771 points

What specifically are you asking?

Are you inquiring if the device itself uses schmitt triggers?

Are you asking if you can put a schmitt trigger externally to the device?

-Bobby

0 yi-ling ho over 4 years ago

Prodigy 20 points

Because I2C CLK have non-monotonic in our DUT PCA9538

We would like to know does this chip support schmitt triggers or not?

Thanks

0 Eric Hackett over 4 years ago in reply to yi-ling ho

TI__Guru 74252 points

Yi-ling,

We are looking into this and will respond by the end of today CST. Thank you for your patience.

Regards,

Eric Hackett

0 BOBBY over 4 years ago in reply to yi-ling ho

TI__Guru 72771 points

All I2C devices should include a 50ns deglitch filter on SDA/SCL. per I2C standard. How long is the monotonic behavior lasting? If I recall correctly, our CMOS inputs have some hysteresis built in but only about 100mV. We don't use schmitt triggers on the SDA/SCL inputs.

-Bobby

0 yi-ling ho over 4 years ago in reply to BOBBY

Prodigy 20 points

50ns deglitch filter on SDA/SCL. per I2C standard it is for Fast-mode but we use Standard-mode

does it have function of deglitch filter ?

The monotonic behavior lasting around 6~7ns

0 BOBBY over 4 years ago in reply to yi-ling ho

TI__Guru 72771 points

Since our device supports fast mode, the standard mode by default will include the 50ns deglitch filter.

If the nonmonotonic signal is below 50ns, then this should not cause any concern.

-Bobby

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PCA9538: does this part support schmitt trigger