TXS0104E: TXS0104E for I2C Level Translation and Pull Values

Saumil Shah60

Part Number: TXS0104E

Hi TI team,

We are using this part for I2C Level Translation.
Our Host Processor Works on 3.3V and Slave IC is on 1.8V.
That is why we used Level Translator in between.

This IC does have Internal 10K Pull up resistor but if my I2C Slave devices need the Lower Value of I2C Pull up, then shall I connect the Pull-up both the sides?

Regards
Saumil

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 243090 points

It does not matter on which side you connect any additional pull-up resistors.

But why do you need them? With the TXS's edge accelerators, it should never be necessary for speed reasons.

0 Saumil Shah60 over 4 years ago in reply to Clemens Ladisch

Intellectual 505 points

Hi Team,

Let us say if my systems need only 2.2K Pull up value for the I2C and if I have used this level translators then how shall I use 2.2K as Pull up with this part?

Regards

Saumil

0 Clemens Ladisch over 4 years ago in reply to Saumil Shah60

Guru 243090 points

The two internal 10 kΩ pull-up resistors are in parallel. To get the equivalent of 2.2 kΩ, add a 3.9 kΩ pull-up resistor.

Again: what is the reason that your system needs 2.2 kΩ?

0 Dylan Hubbard over 4 years ago in reply to Clemens Ladisch

TI__Mastermind 42600 points

Hey Saumil,

It isn't recommended to use additional pull-ups with this device. Could you explain why it needs to be a smaller pull-up?

0 Saumil Shah60 over 4 years ago in reply to Dylan Hubbard

Intellectual 505 points

Hi,

In this case,

It is a Big Problem.

I have connected total of 6 devices on the same I2C Lines.

5 of them are working on the 3.3V and only one is working on 1.8V.

Anyhow one side my I2C lines need the Pull up for the Other devices as well as we have calculated the Pull-up Values then it is Coming around 2.2K.

It seems that in my case this Level translator is not usable.

Regards

Saumil

0 Clemens Ladisch over 4 years ago in reply to Saumil Shah60

Guru 243090 points

Why do you think it is not usable? Does it not work when you are testing it?

How did you calculate the 2.2 kΩ value? It is likely that the TXS's edge accelerators make your calculation invalid.

0 Saumil Shah60 over 4 years ago in reply to Clemens Ladisch

Intellectual 505 points

Hi Team,

So Do you mean to say Shall we try without Pull-up with Level Translators?

Regards

Saumil

0 Clemens Ladisch over 4 years ago in reply to Saumil Shah60

Guru 243090 points

Yes.

0 Saumil Shah60 over 4 years ago in reply to Clemens Ladisch

Intellectual 505 points

OK, We will try the same and get back.

Regards

Saumil

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TXS0104E: TXS0104E for I2C Level Translation and Pull Values