DS26LV32AT: On hold the last state output

prabhakaran Gnanasekaran

Prodigy 30 points

Part Number: DS26LV32AT

Hi All,

We have used this IC in our application.IC part number : DS26LV32ATMX/NOPB

our Problem:

The output pins of this IC is holding the the last state output until we give the next input.

If input HIGH - output HIGH

Next If open the inuput- it is holding the last state (HIGH)

If given input is LOW - output is LOW

Next If open the inuput- it is holding the last state (LOW)

Please help us how to solve this issue.

We are using Rt = 120ohm, but we haven't use any pullup or pulldown at the input pins (As datasheet recomend)

Regards,

G.Prabhakaran

over 5 years ago

0 Max Robertson over 5 years ago

TI__Guru 62910 points

Hello,

When the input is removed, the termination resistor will pull the two halves of the differential signal together to create a differential input voltage close to 0 V. This is near the receiver's switching threshold, and since there is typically 35 mV of hysteresis in this part the output may not toggle. You could resolve this by pulling the (+) line high and the (-) line low so that the device sees a large enough differential input voltage (e.g., one exceeding the VTH specification) to produce a high level output even when no other inputs are connected.

Please let em know if this is unclear or if you have any other questions.

Regards,
Max

0 prabhakaran Gnanasekaran over 5 years ago in reply to Max Robertson

Prodigy 30 points

Hi Max,

Thank you very much, Shall we use like below circuit for to resolving the issue?

0 Max Robertson over 5 years ago in reply to prabhakaran Gnanasekaran

TI__Guru 62910 points

Yes, this circuit will make sure that the receiver sees a "high" level even if nothing is driving the bus, and so it should give a high-level output until something intentionally drives it low.

Max

0 prabhakaran Gnanasekaran over 5 years ago in reply to Max Robertson

Prodigy 30 points

Thank you very much for your answers.

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DS26LV32AT: On hold the last state output