TXB0108: Not working with LCD

Rahul Kadlag

Part Number: TXB0108
Other Parts Discussed in Thread: TXU0104, TXS0108E

Hi,

We used TXB0108 in between MCU (3V3 CMOS logic) and LCD ( 5VTTL logic), we faced issue with LCD function not for all but some LCD characters not displayed .

1. Can we use TXB0108 in between MCU and LCD(2x 16)?

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 316510 points

TXB translators have many restrictions (see the datasheet). I suspect that you have pull-up/-down resistors or too-long traces/cables, but this is impossible to determine without the schematic.

0 Rahul Kadlag over 2 years ago in reply to Clemens Ladisch

Prodigy 80 points

We have not added pullup/pulldown, see the below image for your reference ,

0 Clemens Ladisch over 2 years ago in reply to Rahul Kadlag

Guru 316510 points

But you have 100 pF capacitors. Those will certainly prevent the TXB from working.

For unidirectional signals, use unidirectional translators like the TXU0104.

0 Rahul Kadlag over 2 years ago in reply to Clemens Ladisch

Prodigy 80 points

I tried with removed those capacitor, still its not working.

When we checked data lines on DSO, data line is not properly reach to 0V (GND) its is 480mV. see the image below

0 Clemens Ladisch over 2 years ago in reply to Rahul Kadlag

Guru 316510 points

0.5 V is probably not a problem. But it shows that there is a load somewhere.

0 Rahul Kadlag over 2 years ago in reply to Clemens Ladisch

Prodigy 80 points

Yes, How this is possible. because LCD does not required too much power.

0 Rahul Kadlag over 2 years ago in reply to Rahul Kadlag

Prodigy 80 points

Is there any other option to replace the TXB0108 ?

0 Clemens Ladisch over 2 years ago in reply to Rahul Kadlag

Guru 316510 points

If you want a pin-to-pin replacement, try the TXS0108E (which is a passive switch with internal pull-up resistors and edge accelerators). It might or might not work.

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TXB0108: Not working with LCD