PCA9306: act as an I2C buffer?

justifice zhou

Part Number: PCA9306
Other Parts Discussed in Thread: SN74LVC2G66

Hi,

if I connect VREF1 and VREF2 both to 3.3V, and I don't need the voltage translator function.

Can I use it as I2C buffer? When enabled, side 1 and side 2 are connected together, when disabled, side 1 and side 2 are not connected together.

If it can be used as I2C buffer, can I use it to replace TCA9511 if I don't need READY signal?

over 2 years ago

+1 Clemens Ladisch over 2 years ago

Guru 271820 points

The PCA9306 is a passive switch and does not buffer the signals.

You can use the PCA9306 to disconnect two buses (by pulling EN low). But if this is the only feature you need, use a simpler switch like the SN74LVC2G66.

0 justifice zhou over 2 years ago in reply to Clemens Ladisch

Intellectual 400 points

Clemens,

thanks.

Then when PCA9306 EN=1, SDA1 and SDA2 are connected together through an internal resistor, then will there be current flowing through the internal path? if one side is 1.8V, the other side is 3.3V, it seems that the current is large.

+1 Clemens Ladisch over 2 years ago in reply to justifice zhou

Guru 271820 points

The internal connection is through a MOSFET. The gate is connected to EN; the transistor switches on only when either SDA1 or SDA2 is pulled low. When the I/Os are not driven low, then V_GS = 0 V, there is no connection, and the I/O voltages are determined by the pull-up resistors.

See [FAQ] How do the LSF translators work?

Interface

Interface forum

PCA9306: act as an I2C buffer?