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VOL(max) < 0.18V device for I2C level shifting

Ryuji
Guru 20090 points
Other Parts Discussed in Thread: DS90UB913A-Q1, TCA9517, TCA9517-Q1

Hello,

Are there any device which have 0.18V of  VOL(max) ? 

Currently our customer connected DS90UB913A-Q1 to ISP.
The DS90UB913A-Q1 VOL(max) is 0.4V and VIL(max) of ISP is 0.18V(VDDIO * 0.1V, VDDIO=1.8V).
Thus I would like to recommend voltage level shifter. However, I couldn't found the device of 0.18V VOL(max).

Best Regards,
Ryuji Asaka 

 

  • 0
    TI__Expert 6335 points

    Ryuji,

    Since this is for I2C, my recommendation is an I2C-specific-level-shifter, the TCA9517. The VOL on its 'A' port is 0.1V.

    The 'A' port of the TCA9517 should connect to the ISP. The 'B' port should connect to the DS90UB913A-Q1.

    I don't recommend the generic bi-directional level shifters (the TXS series) because they produce a VOL > VIL.

    The input and ouput of the TXS pins are essentially connected by a pass-gate transistor (NFET). Simplified, VOL = VIL + R_NFET*(I_NFET). So 400 mV into a TXS device will produce > 400 mV out.

    The only way to reduce VOL on a TXS device would be to add an external pulldown resistor on the output (i.e. voltage divider), which is not very convenient. It also will hurt the VOH, hence my suggestion of the TCA9517.

    I am going to move this thread to the I2C forum, where you will get better support for the TCA9517. Thanks.

    Best Regards,
    Nirav

  • 0 in reply to Nirav Patel
    Guru 20090 points
    HelloNirav san,

    Thank you for the reply.
    I will check the TCA9517.
    Are there any plan of automotive qualified version (TCA9517-Q1)?

    Best Regards,
    Ryuji Asaka