Difference btw TCA9406 and TCA9517 as a I2C level translator

ANANTHA PADMANABHA

Other Parts Discussed in Thread: TCA9517, TCA9406

Hello All,

We are facing some strange issue while we use TCA9406 and TCA9517 as a I2C level translator on our board for touch screen interface.

when we use I2C touch controller (i2c interface) with TCA9517 it works fine & no issues.

But when we use same I2C touch controller with TCA9406, it gives timedout error (SDA line not releasing).

We tried with both 100Khz and 400Khz I2C speed.

Anyone one has face these type of issues, kindly share your valuable inputs & feedback.

Thanks & Best Rgds

Ananth

Hardware Engineer

Bangalore, India

over 9 years ago

Daniel Hartung over 9 years ago

TI__Mastermind 28915 points

Hey Ananth,

I have moved this question to a forum better suited for your needs

Thanks,
Daniel

AGXIN over 9 years ago

Intellectual 510 points

Hi sir

I think u have used an external pull up resistor in TCA9517 , what is the value u have used ?

have u removed this pull up resistor while mounting TCA9406 ?

Adding lower value pullup resistors will effect VOL levels

Have u probed the line when using TCA9406 ?

ANANTHA PADMANABHA over 9 years ago in reply to AGXIN

Prodigy 80 points

Hi Daniel & Agxin,
Thank you for your speedy response.

Yes we have tried with 2K2 & 4K7 on TCA9517 since there is no pull up on this level shifter.
Yes, we have removed these external pull up while using TCA9406 (Since it has internal PU)

We have probed the signals & found SDA line not releasing / Permanently low.

Best Rgds
Ananth

AGXIN over 9 years ago in reply to ANANTHA PADMANABHA

Intellectual 510 points

Hi
Is it possible to isolate the SDA line from the bus connecting at the repeater end and probe the line ?

Siby James over 9 years ago in reply to AGXIN

TI__Expert 5140 points

Another thing to consider:

TCA9406 is a voltage translating switch, whereas TCA9517 is a I2C buffer that has voltage translating feature.

Do you have a heavily loaded bus? Or is your trace length very long?

Thanks,
Siby

Interface

Interface forum

Difference btw TCA9406 and TCA9517 as a I2C level translator