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TXS0104E: TXS0104E

Buck Patel
Prodigy 50 points
Part Number: TXS0104E
Other Parts Discussed in Thread: INA226

I am using TXS0104E 4-Bit Bidirectional Voltage-Level Translator to connect to a TI battery monitor (I2C bus connection)  INA226.

See Page 8 of TXS0104E data sheet.  Vccb is 3.3V.   Vil  Low-level input voltage, claims for "B-port I/O"  = 0.15V (max), .Is the 0.15V a typo?

What logic output buffer drives to such a low voltage ????  

Please explain 

Thanks

Buck Patel

  • 0
    Guru 316940 points
    The TXS uses passive switches; when on, they behave like resistors with at most 250 Ω (typical 20 Ω).

    The specified VIL value is not the maximum at which the device switches, but only the maximum at which the VOL value in section 6.6 can be reached (the difference between VOL and VIL is the voltage drop over the switch). If the current through the switch is smaller than the VOL test condition of 1 mA, or if the VOL can be higher, then it is not necessary for the input voltage to be lower than that VIL.

    And CMOS output buffers have a voltage drop linearly dependent on the current, so they will indeed drive to such a low voltage (as long as you use only the TXS's internal 10 kΩ pull-ups and do not add other pull-ups).
  • 0
    TI__Guru 62170 points
    Thanks Clemens for pitching in and I agree.

    Buck,
    The TXS is not a logic buffer which have active drive for high and low conditions, but passive FET based switches internally.
    There is an app note which talks about the factors on which the output Vol for the TXS(and LSF) depends on:
    www.ti.com/.../scea056.pdf

    Will create an FAQ based on this as I have come across this question many times.