PCA9306: PCA9306

DOV SEGAL

Prodigy 30 points

Part Number: PCA9306

Hello

I am using PCA9306EVM evaluation module to test PCA9306 device to my card.

Power supply:

VDPU1 = 1.8V.

VDPU2 = 2.6V

Input signals:

SDA1 = 370KHz , level 1.8V

SCL1 = 370KHz , level 1.8V

The output on SDA2 SCL2 is distorted, not ok.

If I change:

SDA1 = 50KHz

SCL1 = 50KHz

Its ok.

Way it’s not ok on 370KHz?

Thanks & Best Regards

Dov Segal

Senior Hardware Engineer

OSR R&D Israel LTD.

@:dov.segal@osrenterprises.com

M: +972 (54) 4676731

O: +972 (0) 3 5093330

over 1 year ago

0 Tyler Townsend over 1 year ago

TI__Mastermind 47188 points

Hi Dov,

Do we have any scope captures showing the input and output of the device at these two frequencies 50KHz and 370kHz. I need to understand what a distorted signal looks like to you.

What load is being driven on both sides of the PCA9306, or is it only EVM that is being tested?

Regards,

Tyler

0 Clemens Ladisch over 1 year ago

Guru 316640 points

The PCA9306EVM comes with 10 kΩ pull-up resistors. When you want to use high speeds with a high-capacitance bus (i.e., when you have long cables), then you need stronger pull-up resistors. See section 3 of the PCA9306EVM manual for where to solder them.

What values to use depends on the actual capacitance of your setup; you have to check the waveforms with an oscilloscope.

0 Jack Guan over 1 year ago

TI__Mastermind 40046 points

Hey Dov,

It is possible that the size of the pullups were sized incorrectly thus not able to meet the required data rate. Please help see I2C Bus Pull-Up Resistor Calculation for further clarification.

Regards,

Jack

0 DOV SEGAL over 1 year ago

Prodigy 30 points

Hi Tylor

Yes only the EVM that is being tested.

I connect input EVM to signal generator and the output is connect to Scope.

Regards

Dov

0 Jack Guan over 1 year ago in reply to DOV SEGAL

TI__Mastermind 40046 points

Hey Dov,

I see- thanks for clarifying. Were you able to implement the changes mentioned by Clemens to resolve the issue?

Regards,

Jack

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PCA9306: PCA9306