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TLIN1029-Q1: LIN Vout Spec Definition

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Replies: 3

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Part Number: TLIN1029-Q1

Hello,

Specs are defined differently for TLIN1029-Q1's LIN VOH and VOL below and above VSUP = 7 V. For example, the Min VOH is a ratio (× 0.85) of VSUP for VSUP of 7 V and above while it's a voltage (3 V) for VSUP of less than 7 V. The same is applied to VOL, too. I suspect it comes from the internal architecture, but what exactly is the reason behind this?

Best regards,
Shinichi Yokota

  • Yokota-san,

    LIN generally has an open-drain architecture that rely on a pullup resistance to achieve the rise time timing requirements.  At higher supply voltages there is enough current through this resistance to charge the capacitive load and meet the rise time requirement.  However, the TLIN1029-Q1 was designed to also operate in lower voltage applications with a supply voltage less than 7V.  In these lower voltage applications, there is not enough current through the pullup resistor to meet the rise time requirements.  Therefore, the TLIN1029 has a current injection circuit that turns on when the supply voltage is less than 7V and will help the transition meet the rise time requirement by injecting a little extra current.  This is the reason for the two different specifications when the supply is greater than or less than 7V.

    Regards,

    Jonathan

  • In reply to Jonathan Nerger:

    Jonathan-san,

    Thank you for your comments.

    From the internal architectural point of view, will the VOH and VOL be constant across the VSUP range of 4 to 7 V?

    Best regards,
    Shinichi Yokota

  • In reply to Shinichi Yokota:

    Yokota-san,

    No I do not think it is correct to say values will be constant across the VSUP range of 4 to 7 V.  Rather the values will still scale with the supply voltage.  The minimum VOH and maximum the VOL will just have different limits and not follow still follow the percentages of VSUP when the supply is greater than 7 V.  The VOH will always be at least 3V, and the VOL will be less than 1.2 V.

    Best Regards,

    Jonathan