TXB0106PWR output problem

Burak b

Other Parts Discussed in Thread: CDCLVC1108, TXB0106

Hello,

I am using TXB0106PWR level translator in my circuit and i have a problem about translating to 5V from 3.3 V;

I use TXB0106PWR in my circuit as below:

I drive input port A (3.3 V) , but I can not get 5V at the outputs (B); when I look at the outputs by using multimeter, I read 2.3 V; but when i use osciloscope, I can see 5V, I drive this level translator by a xilinx FPGA through cdclvc1108 ti clock buffer;

I also use other txb0106s in my circuit for other ports; i read 5v at some outputs by using multimeter and osciloscope; these are directly driven by FPGA, but I can see at some ports level unstability at ouputs on multimeter,

Why I read different at the outputs, and unstablity occurs at some pins; I don't use any load at he outputs. I directly read by multimeter or osciloscope

Best regards

Burak

over 9 years ago

0 Clemens Ladisch over 9 years ago

Guru 317000 points

The schematic is missing.

0 Nirav Patel over 9 years ago

TI__Expert 6335 points

Burak,

Please re-send your schematic. I can't view it. Also, what is the Model # of your multimeter? Perhaps it is drawing too much current and therefore pulling down the VOH.

Best Regards,
Nirav

0 Burak b over 9 years ago in reply to Nirav Patel

Prodigy 50 points

Dear Nirav,

My schematic is:

the cdclvc input is driven by an artix FPGA, we see at the outputs of level translator 2.3 V, while using multimeter (tried our two multimeters; fluke and wavetek); sorry about late reply, i was on holiday

0 Burak b over 9 years ago in reply to Burak b

Prodigy 50 points

I can't paste the image; ı send it as attachmentschematic.docx

0 Clemens Ladisch over 9 years ago in reply to Burak b

Guru 317000 points

Footnote 1 in section 6.3 of the datasheet says:

The A and B sides of an unused data I/O pair must be held in the same state, i.e., both at V_CCI or both at GND.

A6/B6 must not be floating.

(However, this should not affect the voltage level on the other pins.)

0 Burak b over 9 years ago in reply to Clemens Ladisch

Prodigy 50 points

Dear Ladisch,
Thank you for your answer, yes for unused pins, we must do that, but as you said, that doesnot solve problem, also i have seen same unstability problem at pins of other txb0106 in my circuit, when i look at outputs using multimeter, why it behaves like this?

0 Burak b over 9 years ago in reply to Burak b

Prodigy 50 points

İ have read that the txb0106 translators need low capacitance, high impedance outputs from some forums for this problem; when we use this translator to drive another circuit/system at outside; do we need pull up/down at the outputs of translator, the outer system input impedance is high and low capacitance; how is the cable lenght to system; how should be the schematic at the outputs of the translator and the input impedance, capacitance of the outside part that is driven in order to provide stable voltage translation of txb0106

0 Clemens Ladisch over 9 years ago in reply to Burak b

Guru 317000 points

The schematic does not show what the output is connected to. But it appears you get the problem only with the multimeter, so I guess this is a problem with the multimeter.

Logic

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TXB0106PWR output problem