TXS0108E: Can't Work

HungLin Hsu

Part Number: TXS0108E
Other Parts Discussed in Thread: TXS0102

Hi,

My design is following. Before IC the signals are doing well, but after the IC, it can't bi-direction. what should I do?

over 5 years ago

0 Clemens Ladisch over 5 years ago

Guru 322000 points

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0 HungLin Hsu over 5 years ago in reply to Clemens Ladisch

Prodigy 220 points

Hi,

As following

0 Emrys Maier over 5 years ago in reply to HungLin Hsu

TI__Guru* 97486 points

Hi HungLin,

Is this happening on all channels?

Can you share a scope shot from one of the channels that is failing for you?

Also, can you show all devices connected (including pull-up or pull-down resistors) that the channels are connected to? It is also helpful to know if there are connectors or long wires involved in any connections.

0 HungLin Hsu over 5 years ago in reply to HungLin Hsu

Prodigy 220 points

Hi,

If I didn't any loading at A side. Signals can't achieve to gnd (fig1). Sense I connected to our IC, signals became bad. (fig2)

fig1.

0 Clemens Ladisch over 5 years ago in reply to HungLin Hsu

Guru 322000 points

Do you have long traces, cables, or connectors? The traces show that there is a lot of ringing; this can cause the TXS to oscillate.

0 HungLin Hsu over 5 years ago in reply to Clemens Ladisch

Prodigy 220 points

Hi, Clemens,

output traces are long. but I test TXS0102 did not happen this status. so how could I improve?

0 Emrys Maier over 5 years ago in reply to HungLin Hsu

TI__Guru* 97486 points

Hi HungLin,

The most common way to reduce ringing from long traces is to add a small series resistor at the output of the device driving the trace. 20 to 30 ohms should be enough to reduce the ringing. Some additional info can be found here:

The increase in low-state voltage is caused by the current driving through the TXS device. When an input is LOW for a long period of time (longer than a few nanoseconds), then this device operates very similarly to the LSF family of voltage translators. There is an explanation of this basic concept in this video specifically related to LSF, but it also applies to the TXS device:

https://training.ti.com/down-translation-lsf-family?cu=1134826

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TXS0108E: Can't Work