THVD1500: DE and RE Maximum Rise/Fall Time

Greg

Expert 2031 points

Part Number: THVD1500

Is there a maximum rise/fall time to switch the the DE and RE inputs of the THVD1500? I am planning on using a cheap optocoupler to drive the DE input, and I want to know if there are any concerns about how fast the signal switches state. I looked through the data sheet but didn't see this specification. Sorry if I missed it.

Thanks,

Greg

over 6 years ago

0 Miguel Robertson over 6 years ago

TI__Guru 62920 points

Greg,

No, there isn't a limitation on this. I wouldn't recommend holding the logic inputs at an intermediate voltage for indefinitely long periods of time since this can result in higher current consumption, but for any reasonable transition behavior from an optocoupler I wouldn't be concerned.

Max

0 Greg over 6 years ago in reply to Miguel Robertson

Expert 2031 points

Hi Max,

Thanks for the answer. Would the higher current consumption be damaging to the device? I certainly wouldn't do that on purpose, but I'm curious what would happen if it happened.

Regards,

Greg

0 Miguel Robertson over 6 years ago in reply to Greg

TI__Guru 62920 points

Greg,

No, I wouldn't expect immediate damage. (We often sweep the input voltage slowly in order to measure the threshold level of these inputs.) There may be degradation in the expected device lifetime with prolonged exposure, although this is difficult to quantify.

Regards,
Max

0 Greg over 6 years ago in reply to Miguel Robertson

Expert 2031 points

Thanks Max. I appreciate the help. I'll have it slew reasonably fast and make sure it never hangs out in no man's land.

Regards,

Greg

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THVD1500: DE and RE Maximum Rise/Fall Time