TXS0108E-Q1: About pull-up resistor

Koji Hayashi92

Mastermind 6990 points

Part Number: TXS0108E-Q1
Other Parts Discussed in Thread: TXS0108E, TXS0101

Hi All

Data Sheet has the following description.

RPUA and RPUB have a value of 40 kΩ when the output is driving low.

RPUA and RPUB have a value of 4 kΩ when the output is driving high.

Please tell me the mechanism of change ?

Also, how much is the resistance variation each ?

Best Regards,

Koji Hayashi

over 6 years ago

0 ShreyasRao over 6 years ago

TI__Guru 59770 points

Hi Koji-san,

Please refer to the app note about the TXS working here below:

http://www.ti.com/lit/an/scea044/scea044.pdf

0 Koji Hayashi92 over 6 years ago in reply to ShreyasRao

Mastermind 6990 points

Hi Shreyas-san

Thank you for quick response.

I read this file.

But I couldn't find.

Please tell me the passages corresponding to answer.

Best Regards,

Koji Hayashi

0 ShreyasRao over 6 years ago in reply to Koji Hayashi92

TI__Guru 59770 points

Koji-san,

With respect to the variation of the internal resistors, we do not have the simulation of the TXS0108e device nor it is mentioned in the datasheet.
Based on the TXS0101/2 simulation, the variation can be from 6.5K to 15k for the 10k resistors which corresponds to 35-50%. Based on this, I would estimate that the TXS0108 resistor variation could range from 26k to 60k for the 40k resistor and 2.6k-6k.

0 Koji Hayashi92 over 6 years ago in reply to ShreyasRao

Mastermind 6990 points

Hi Shreyas-san

Thank you for quick response.

I understood about the variation.

( That it varies from -35 to 50% )

Can not disclose the principle of operation in which the resistance value changes ?

Best Regards,

Koji Hayashi

0 ShreyasRao over 6 years ago in reply to Koji Hayashi92

TI__Guru 59770 points

Koji-san,

I don't have an answer for the mechanism of switching. We do not have access to design information(which is proprietary) and many designers who worked on this device back in 2007 may not be here anymore. Why do you need to know the mechanism of switching?

0 Koji Hayashi92 over 6 years ago in reply to ShreyasRao

Mastermind 6990 points

Hi Shreyas-san

Thank you for quick response.

My customer feel a sense of incongruity that the resistance value changes.

So they wants to understand for the mechanism of switching.

I told them in advance that it is difficult to explain the internal structure of the circuit.

Best Regards,

Koji Hayashi

0 ShreyasRao over 6 years ago in reply to Koji Hayashi92

TI__Guru 59770 points

Koji-san,
Thanks. Let me know if there is anything else.

0 Koji Hayashi92 over 6 years ago in reply to ShreyasRao

Mastermind 6990 points

Hi Shreyas-san

Thank you for response.

I will contact you if I have any questions

Best Regards,

Koji Hayashi

Logic

Logic forum

TXS0108E-Q1: About pull-up resistor

http://www.ti.com/lit/an/scea044/scea044.pdf