TXS0104E-Q1: I2C Hub Function

Evan Wang

Expert 5540 points

Part Number: TXS0104E-Q1

Hi TI Expert,

Could we use the TXS0104E-Q1 as I2C Hub?

The Idea as below, VCCA = VCCB = 3.3V

Short A1 & A2 and A3 & A4 together.

Except the pullup resistance on SDA/SCL side will be 10kohm//10kohm = 5kohm, do you have any concerns about below structure?

Thank you.

8 months ago

0 Clemens Ladisch 8 months ago

Guru 263000 points

The pull-up resistance will be 2.5 kΩ.

What is the actual problem you're trying to solve? The TXS is a passive switch and does not isolate the two sides from each other. You probably want an I²C buffer.

0 Jack Guan 8 months ago

TI__Mastermind 21111 points

Hey Evan,

In addition to Clemens' response, please be mindful of the SDA1/SDA2 signals as they can cause possible bus contention issues if one of the channels are communicating back to upstream device. Furthermore- when SDA drives low, it will now have to sink the current as a result of channel 1 and channel 2.

Regards,

Jack

0 Evan Wang 8 months ago in reply to Jack Guan

TI__Expert 5540 points

Hi Clemens, Jack,

Thank you for the sharing.

We just want to find a easier way to achieve the I2C hub function.

I check the ti.com and we can use the TCA9548-Q1 for it but we only need 2 ch.

It seems that the VOL during low status might be a problem since you mention the sink current will be channel 1 + 2.

As for the bus contention issue you mentioned, if channel 1 / 2 and the master all have different I2C address, it should be OK right?

0 Clemens Ladisch 8 months ago in reply to Evan Wang

Guru 263000 points

What exactly do you mean with "hub"? What is the actual problem you're trying to solve?

0 Evan Wang 8 months ago in reply to Clemens Ladisch

TI__Expert 5540 points

Hi Clemens,

Means we want to make a 1 to 2 signal buffer device.

Output 1 & output 2 has the same signal as input.

So we want to know if we try to implement such functionality, is TXS0104E-Q1 able to do that?

0 Clemens Ladisch 8 months ago in reply to Evan Wang

Guru 263000 points

You could simply use four pieces of wire.

What is the actual problem you're trying to solve?

0 Jack Guan 8 months ago in reply to Clemens Ladisch

TI__Mastermind 21111 points

Hi Evan,

Could you see if the TCA9543A can be used in your application? I would note that this device is capable of operation up to 400KHz however.

Regards,

Jack

0 Evan Wang 8 months ago in reply to Jack Guan

TI__Expert 5540 points

Hi Jack,

Appreciate the feedback but since we need the AEC-Q100 device so I will still recommend the TCA9548-Q1 even it's a 8-ch device.

Close this case first.

Thank you all.

Logic

Logic forum

TXS0104E-Q1: I2C Hub Function