THVD1510: What's the threshold and hysteresis voltage in DE/RE pin?

Wiky Liao

Part Number: THVD1510
Other Parts Discussed in Thread: SN74LVC1G17, TLV7031

Hi Team,

May I have the threshold voltage for DE and RE separately? I don't find it in datasheet. We face a issue in customer side, we point out DE/RE have significant delay which may cause problem, but still want to know why the RX have LOW signal pulse. If you have other view for this case, please also share to me, thanks a lot!

Yellow: RX

Blue: TX

Pink: A/B

Green: DE/RE

over 3 years ago

+1 Hao L over 3 years ago

TI__Mastermind 25705 points

Wiky,

The DE and REB pins follow the TTL logic (0.8V and 2.0V).

I'm not aware of such glitch. Is the delay consistent or varying with the ramping time?

0 Wiky Liao over 3 years ago in reply to Hao L

TI__Intellectual 1890 points

Hi Hao,

Thanks for your data. I think the glitch due to DE/RE pin voltage jump into 0.8V~2.0V, so THVD1510 can't judge if it is drive mode or receive mode.

0 Hao L over 3 years ago in reply to Wiky Liao

TI__Mastermind 25705 points

Wiky,

Your hypothesis sounds right to me. Is it possible to better control the control pin?

0 Clemens Ladisch over 3 years ago in reply to Hao L

Guru 314190 points

To drive the DE/RE pins with proper digital signals and to ensure that both use the same value, you can use a logic buffer with a Schmitt-trigger input, e.g., SN74LVC1G17.

If you want to precisely control the switching threshold, you have to use a comparator, e.g., TLV7031.

0 Wiky Liao over 3 years ago in reply to Hao L

TI__Intellectual 1890 points

Hi Hao,

Already suggest customer to remove the capacitor at DE/RE pin, makes the slope straightly, and it works good now.

0 Wiky Liao over 3 years ago in reply to Clemens Ladisch

TI__Intellectual 1890 points

Hi Clemens,

Thanks for your comments, customer feedback they are paralleling capacitor at DE/RE pin as filter, suggest to remove and it works good now.

0 Hao L over 3 years ago in reply to Wiky Liao

TI__Mastermind 25705 points

Thanks for your update. Good to know.

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THVD1510: What's the threshold and hysteresis voltage in DE/RE pin?