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DS90UH929-Q1: Question about VTERM in the IBIS model

Intellectual 1025 points

Replies: 1

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Part Number: DS90UH929-Q1

Hi, team.

VTERM in the IBIS model is defined as "NC".

Does VTERM have an impact for the TMDS input impedance and the characteristics?

Please give me your advice.

Best Regards,

  • Hello,

    VTERM does not change the TMDS input impedance.  VTERM is an input pin, used for determining the TMDS input resistor termination voltage.

    In the datasheet, (sht9DS90UB929-Q1), it refers to section 4.2.5 in the HDMI v1.4b specification .  In the HDMI 1.4b standard the termination voltage is called AvCC, see Figure 4-31.  

    In AC coupled applications, VTERM is connected to 1.8v (section 7.3 of the ds90ub929-q1 datasheet). 

    In the HDMI v1.4b standard see table 4-27, operating voltage is AvCC  - 150mv to AvCC - 1560mv

    In DC coupled applications, VTERM is connected to 3.3v (section 7.3 of the ds90ub929-q1 datasheet)

    In the HDMI v1.4b standard see table 4-25, operating voltage AvCC-37.5mv to AvCC-300mv.

    In the HDMI standard Figure 4-32 shows the eye mask for TP2 HDMI Sink for Automotove application.

    in Keysight ADS, there is an HDMI Design kit that can be used for HDMI source to DS90UB929-Q1 IBIS HDMI modeling.

    The appropriate DC voltage depending on application is connected to pullup resistors external to the IBIS component.

    Thank you,

    Joe Quintal