TXB0102: TXB

rachel tang

Prodigy 30 points

Part Number: TXB0102
Other Parts Discussed in Thread: TXU0102

Tool/software:

In the datasheet of TXB0102, why should the VCCA<=VCCB? The architecture of TXB is symmetrical.

1 month ago

0 Clemens Ladisch 1 month ago

Guru 259820 points

There is a protection diode between VCCB and VCCA; see Biasing Requirements for TXS, TXB, and LSF Auto-Bidirectional Translators.

0 rachel tang 1 month ago in reply to Clemens Ladisch

Prodigy 30 points

Why need a internal protection diode between VCCB and VCCA? Could you help to descripe the detail of the protection diode? Thanks~

0 Jack Guan 1 month ago in reply to rachel tang

TI__Mastermind 20661 points

Hi Rachel,

The internal diode between VCCA/ VCCB minimizes leakage from VCCB-> VCCA side during normal operation. Is there a concern with this requirement? If so, you may see fixed direction translators such as the TXU0102 that does not have this biasing requirement.

Thanks,

Jack

0 rachel tang 1 month ago in reply to Jack Guan

Prodigy 30 points

I am just learning about TXB architecture and have some questions about VCCA<=VCCB, and the diode is not depicted in the architecture diagram.

What is the leakage path from VCCB to VCCA?

0 Jack Guan 1 month ago in reply to rachel tang

TI__Mastermind 20661 points

Hey Rachel,

There are no concerns with using the device where VCCA<= VCCB as it is supported by the device. It is in the condition that VCCA > VCCB that becomes an issue as the internal protection diode becomes forward biased, highlighted similar to the app note Clemens' referenced above.

The diode is not shown in the architecture to keep diagram simple/ top level.

Thanks,

Jack

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TXB0102: TXB