TXB0104: VCCA and VCCB tolerance

Lars Wallden1

Part Number: TXB0104
Other Parts Discussed in Thread: TXU0204

Tool/software:

Hello, can the voltage of VCCA exceed VCCB to some extent? I do understand the datasheet specifies that VCCA must not exceed VCCB, but is there some margin in this or another pin-compatible circuit that can accept a higher or varying difference of VCCA towards VCCB?
The application uses one UART RX/Tx and 2 GPIO, and the package is RGY.
Thanks in advance.

20 days ago

0 Jack Guan 20 days ago

TI__Mastermind 28121 points

Hi Lars,

Yes, the IV curve is documented in Biasing Requirements for TXS, TXB, and LSF Auto-Bidirectional Translators with increasing leakage current as VCCA> VCCB gap widens.

Please reach out for any additional questions.

Regards,

Jack

0 Lars Wallden1 20 days ago in reply to Jack Guan

Prodigy 40 points

Hi Jack,

Thanks for the fast response and the attached document. Is there another TI circuit that could accept a higher VCCA/VCCB ratio that is compatible with the TXB0104?

Regards,

Lars

0 Jack Guan 20 days ago in reply to Lars Wallden1

TI__Mastermind 28121 points

Hi Lars,

If the auto-bidirectionality is not a must-have, then the TXU0x04 can be realized here. There are not power supply restraints with the TXU-Type devices.

Regards,

Jack

0 Lars Wallden1 20 days ago in reply to Jack Guan

Prodigy 40 points

Hi Jack,

Looking quickly at the datasheet, it seems as if the TXU0204 could work, it does not have the exact pinout that our PCB expects but probably good enough so that we can rework it for the prototypes and then update the design. The circuit is a UART level changer and is now done as (from port A1- A4):
A1: Tx ->
A2: Rx <-
A3: RTS ->
A4: CTS <-
So switching A2 ports with A3 ports would fix the issue, at least it seems.
We can get the circuits and rework a board to check if that works.

Thanks for the advice.

Regards,

Lars

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TXB0104: VCCA and VCCB tolerance