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OPA1622: OPA1622 enable pin behaviour

Part Number: OPA1622

Hello dear TI community.

I've got rahter simple question about enable pin of OPA1622 amplifier.

I'll use demux 2:1 IC to switch enable signal between pairs of OPA1622 in my design.
I picked SN74LVC1G18 for this job - input of this demux will be always high state (input will be feeded by voltage supervisor and let's consider that voltages will be within range // supervisor output will be pulled up to 5VDC).

Because I want to avoid relays etc. my question is did I picked right solution or maybe I should consider different approach?
Another question is if I turn up one OPA1622 with high state signal, does high-impedance OFF-state will turn it off?

Is it safe to use high-impedance OFF-state to turn off that kind of chip?
Or maybe I should add some pull down resistor to that signal in case when it will be high impedance state?

Thank you for helping me.
Have a nice day.

  • Hello Mateusz,

    Thank you for your post, I can help you.

    The enable (EN) pin on the OPA1622 is defined for 2 states, these are: Ven ≤ 0.78V (shutdown mode) and Ven ≥ 0.82V (enabled). These threshold levels are reference to the device ground pin. The enable pin can be driven by a GPIO pin from the system controller, discrete logic gates, or can be connected directly to the V+ supply. Do not leave the enable pin floating because the amplifier is prevented from being enabled. Likewise, do not place GPIO pins used to control the enable pin in a high-impedance state because this placement also prevents the amplifier from being enabled.

    Also, make sure the voltages seen at the EN pin do not exceed the power supply recommendations as described in table 6.1 of the datasheet.


  • So if I want my OPA1622 to be disabled then making EN pin a high impedance state is technically a good idea?
    Because there is no other way to make it different with this demux IC.

    So if there is a better way please inform me ;)

  • Hi Mateusz,

    Exactly, placing the enable (EN) pin in high impedance will disable the pin.