TXB0104-Q1: Questions about TXB0104

Jay wang

Part Number: TXB0104-Q1
Other Parts Discussed in Thread: TXB0104, TXU0104, , TXB0304

Hi expert

My customer has some questions about using TXB0104. Customer's PCBs are shown as following.

I introduce Customer's PCBs in brief. The arrows represent the direction of the signal(the output of TXB0104) .The length of flex cable is accurate. Wire on PCB1 or PCB2 is not accurate.

Customer finds that the PCB2 and PCB1 sometimes don't work.

Q1:How does error range of the pullup resistor in TXB0104?

Q2: How is drive capability of the TXB0104?

Q3:What might be the reason you think it's not working properly ？

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 316690 points

1. There are no guaranteed limits.

2., The specified drive strength is 20 µA.

3. The total capacitance of the traces, connectors, and cables is too high for the TXB.

Replace it with the TXU0104.

0 Jay wang over 3 years ago in reply to Clemens Ladisch

TI__Expert 3191 points

thank you for your reply.

For question one, whether does it mean we cannot know the error range of internal pullup resister?

+1 Clemens Ladisch over 3 years ago in reply to Jay wang

Guru 316690 points

A typical tolerance of on-die resistors is ±30 %. But I do not know what technology TI uses for these, and as I said, there are no guarantees.

0 Jay wang over 3 years ago in reply to Clemens Ladisch

TI__Expert 3191 points

thank you for your powerful support

0 Johnny Guo over 3 years ago in reply to Clemens Ladisch

TI__Expert 4910 points

Hi Clemens,

Can you share some load parameter for TXB0104-Q1 if you have? Like what is the suggested capacitor/resistor load range at 10MHz data rates?

Thanks.

Johnny

0 Clemens Ladisch over 3 years ago in reply to Johnny Guo

Guru 316690 points

The datasheet mentions limits of 70 pF and 50 kΩ, but the load should be as small as possible.

0 Johnny Guo over 3 years ago in reply to Clemens Ladisch

TI__Expert 4910 points

Hi Clemens,

Confirm with you, if 20uA in datasheet is the maximum output driving current for TXB0104?

And do we have new bi-directional level-shift socket with stronger driving strength?

Thanks.

Johnny

0 Clemens Ladisch over 3 years ago in reply to Johnny Guo

Guru 316690 points

20 µA is the maximum current for which the electrical characteristics are guaranteed.

The TXB0304 is slightly stronger, but is unlikely to help.

An auto-bidirectional translator cannot have a high drive strength because it does not know which direction is desired. Use a fixed-direction or direction-controlled translator.

Logic

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TXB0104-Q1: Questions about TXB0104