TXB0108PWR used for 5V to 3V3 level conversion

Maxime Torrelli

Other Parts Discussed in Thread: TXB0108

Hello,

I am wondering if I use the TXB0108PWR for a 5V to 3V3 level conversion, is it still possible to connect to the 5V input a signal of only 3V3 without doing any harm to the device? Is it been developped for such application?

Thanks for your help!

over 9 years ago

0 Clemens Ladisch over 9 years ago

Guru 316220 points

The "Recommended Operating Conditions" table in the TXB0108 datasheet does not allow any levels between the high and low levels. 5 V × 0.65 = 3.25 V, so it would just barely fit, but only if the 5 V and 3.3 V supply voltages are accurate enough. This might not be the case in your circuit.

Figure 5 shows the current consumption; at 3.3 V, it might be higher than you want.

This device is not really designed to accept 'wrong' voltage levels.

0 Maxime Torrelli over 9 years ago in reply to Clemens Ladisch

Intellectual 610 points

I understand what you mean. So a solution could be to put a switch to select the input voltage between 5V or 3V3, depending the device connected to the level-shifter. Is it possible to use this device ton "convert" 3V3 to 3V3? Thus, the TXB0108 would only be a ESD protection?

0 Clemens Ladisch over 9 years ago in reply to Maxime Torrelli

Guru 316220 points

The datasheet says:

V_CCA ≤ V_CCB

Logic

Logic forum

TXB0108PWR used for 5V to 3V3 level conversion