TXB0104: buffering TXRX signal issue

Dmitry Petrenko

Part Number: TXB0104
Other Parts Discussed in Thread: SN74AHC245

Tool/software:

I use TXB0104 as a buffer for amplifying signals form TFP2 programator. Power supplied Vcca=Vccb=3V3.
For some reason TXRX signal HI level from TFP2 side is being reduced from 3V3 to 1V by the TXB0104 translator, and it is low output after the translator (so it is no translation of the signal).
OE pin is attached to the Vcc directly. Do have somebody any ideas why its reducing and not giving the output signal?

P.S. TXRX is bi-directional signal

7 months ago

0 Dmitry Petrenko 7 months ago

Prodigy 10 points

0 Clemens Ladisch 7 months ago

Guru 316380 points

The TXB is not a buffer; it reduces the drive strength of the signals.

(A bidirectional buffer is not possible without a direction signal; this would be a transceiver, e.g., SN74AHC245.)

0 Jack Guan 7 months ago in reply to Clemens Ladisch

TI__Mastermind 39986 points

Hi Dmitry,

In addition to Clemens' comments, external pullups and pulldowns are not suggested to be used with this device to not contend with internal 4k series resistors.

Regards,

Jack

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TXB0104: buffering TXRX signal issue