TXB0104QR

Jeff Cohen

Other Parts Discussed in Thread: SN74AXC8T245

Regarding the TXB0104Q Bi-directional Translator: What is the maximum IOH and IOL for a 5V output? The data sheet seems to indicate it is 20UA. Is this the correct number to use?

Thank you ,

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 318050 points

Yes, it's 20 µA. (The outputs are very weak to allow external devices to override the voltage.)

If you care about the drive strength, a TXU translator would be a better choice.

0 Jeff Cohen over 3 years ago in reply to Clemens Ladisch

Prodigy 150 points

Are there any parts in the TXU series in the 12-UFQN package that are bi-directional? The circuit board is already done, and I am seeing signs that the line is overloaded.

0 RD over 3 years ago

Intellectual 280 points

The datasheet recommends using pullup/pulldowns that are 50K or greater in value. If the max IOH was 20uA, this signal would never be driven to the appropriate levels? Could you please recheck to make sure the max drive is actually 20uA? Thanks.

+1 Clemens Ladisch over 3 years ago in reply to Jeff Cohen

Guru 318050 points

The TXU is not bidirectional.

It is not possible to buffer fast bidirectional signals. The TXB cannot be used with long traces, connectors, or cables.

The 50 kΩ limit ensures that the resistor is weaker than the TXB output. (If the resistor were stronger, the output would not work at all.)

0 Jeff Cohen over 3 years ago in reply to Clemens Ladisch

Prodigy 150 points

I will place a 74LV1G125 in series with the output to give it more drive. Thank you very much for your help.

0 Clemens Ladisch over 3 years ago in reply to Jeff Cohen

Guru 318050 points

The '125 is not bidirectional. If you have a direction control signal, use a direction-controlled translator like the SN74AXC8T245.

Logic

Logic forum

TXB0104QR