LSF0102: Suitable Device

Kuan Wei Chen (Kevin Chen)

Part Number: LSF0102
Other Parts Discussed in Thread: TCA9800

Dear Team,

We have a IC PU6 that will outputs 0.6~0.85V I2C signal into PU4 but PU4 max ViL is only 0.4V.

Do you have any I2C buffer or repeater that can accept 0.85V(@3.3V supply) as logic low and out a voltage below 0.4V as logic low?

Kevin

over 6 years ago

0 Clemens Ladisch over 6 years ago

Guru 317460 points

The TCA9800/1/2/3 should be able to do this:

The TCA9800 is able to provide true buffering (rather than a pass-FET solution) without using a static voltage offset or incremental offset. This means that the V_OL on both the A and B sides of the TCA9800 are very low (approximately 0.2 V), helping to eliminate communication issues as a result of fixed V_IL thresholds.

Please see the datasheet for how to design the circuit, especially section 9.4.1.

0 Kuan Wei Chen (Kevin Chen) over 6 years ago in reply to Clemens Ladisch

TI__Genius 9710 points

Dear Clemens,

Can both sides be used with 3.3V?
The bottom test conditions seem to be VI=0V, but when VI=0.85V (still below 0.3*VCC), is the VOL still able to meet the underlying specifications (max <0.26)?

Kevin

0 Clemens Ladisch over 6 years ago in reply to Kuan Wei Chen (Kevin Chen)

Guru 317460 points

The two supply voltages can be identical (see section 10.2.2).

The outputs on both sides are switched digitally, i.e., the actual input voltage on the other side does not matter, as long as it's low.

Logic

Logic forum

LSF0102: Suitable Device