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TLV1805: max voltage in high z

Isee
Expert 4840 points
Part Number: TLV1805

Dear Team,

what is the max voltage  at OUT pin at high-z state? At supply voltage of 3.3V (V- = 0V)

It is planned to pull-up OUT pin with a 10-100k pull-up to 18V

Power-supply of TLV is only present AFTER the 18V

Datasheet 6.1 doesn`t seem to be relevant for this case?

Regards

Andreas

  • 0
    Guru 243220 points

    Section 6.1 says that the voltage at the output must not go above V+ + 0.3 V. (There is a clamping diode from the output to V+.)

    The input pins would allow up to 10 mA through this diode, but there is no specified limit for the output. 0.18 mA is probably OK, but not guaranteed by the datasheet. Also note that the current flows into the power supply connected to V+, and might raise its voltage, which would affect all devices connected to that.

    Consider adding a transistor after the output.

  • 0
    Guru 140200 points

    Hi Isee,

    the TLV1805 has a push-pull output, no open-drain. If you want to have a pull-up resistor at the output of TLV1805 for high-Z conditions, only connect it to the supply voltage pin of TLV1805, as shown in the datasheet in section 8.2 "typical applications".

    Kai

  • 0
    TI__Mastermind 49906 points

    Hello Andreas,

    As Kai and Clemens said, the output has ESD clamps to the V+ line that are there at all times.

    While in shut-down (Hi-Z), you may apply a voltage to the output as long as it stays within the applied supply voltage.

    If the supply voltage is zero, then the ESD diode will clamp within 800mV above of the supply voltage at the time.

    As Clemens warned, the pull-up through the ESD diode could pull the supply up past 3.3V, as most voltage regulators cannot sink current and the supply could rise above 3.3V. Of course, this depends on the total load on the 3.3V line, pull-up current and the time.