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LSF0102: LSF0102

jayashree
Intellectual 680 points
Part Number: LSF0102


Hi Team,

I am using LSF0102DCTR in my design to convert from 3.3V on processor side to 5V on the device end.

I wanted to you people to check my LSF0102DCTR schematics from your end.

I am attaching the schematics pdf of all TI products used in my design, please have a look at it and update me with your review feedback.

With regards,

Jayashree.TI Parts review.pdf

  • 0
    Guru 319490 points

    VREF_B must be connected to EN (it is not a power supply).

    The pull-up resistors are rather small. What speed do you need?

  • 0 in reply to Clemens Ladisch
    Intellectual 680 points

    VREF_B should be connected to EN pin and EN pin to be given power supply you mean. Please explain it to me.

    I was also concerned about the pull up resistors but when I checked datasheet it is recommended to use it. (please refer LSF0102DCTR datasheet Pg no: 15 for same)

    I am using this level translator for i2C signals, so my speed is 400k bits/second.

  • 0 in reply to jayashree
    Guru 319490 points

    Section 9.2.1.1.1 of the datasheet says:

    The 200 kΩ, pull-up resistor is required to allow Vref_B to regulate the EN input and properly bias the device for translation. For additional details on device biasing, see the Understanding the Bias Circuit for the LSF Family video.

    Section 9.2.1.2.1 says:

    For the bidirectional translation configuration (higher voltage to lower voltage or lower voltage to higher voltage), the EN input must be connected to Vref_B and both pins must be pulled up to the HIGH side Vpu through a pull-up resistor (typically 200 kΩ). This allows Vref_B to regulate the EN input and bias the channels for proper translation.

    You do not need such a high current for I²C. 4.7 kΩ resistors on the A and B sides should be sufficient.

  • 0 in reply to Clemens Ladisch
    Intellectual 680 points

    Thanks for the reply.

    I have updated your feedback comments in the schematics and attached the updated schematics of LSF0102 IC.

    Please check it and let me know your inputs.

    In earlier conversion I have attached schematics of all Ti parts that I am using in my design. May I know the review feedback for all those parts?

  • 0 in reply to jayashree
    Guru 319490 points

    Looks OK.

    You might get faster help if you post the relevant parts in the converters and power forums.

  • 0 in reply to Clemens Ladisch
    TI__Genius 16735 points

    Hi,

    As Clemens mentioned, you will have to post a separate post for each part. I only have expertise in the logic and translation devices.

    Thanks!

    -Karan