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PCA9536 Iq

Other Parts Discussed in Thread: PCA9536

I have a question about the Iq for the PCA9536. It lists two modes for standby (see below). I'm not sure whether Vi is the I2C port or the I/O port. I can't imagine why the output port being low would cause the Iq to go up so much. Also it doesn't list Iq for Standby with the I/O = Outputs. We are probably going to have mostly outputs, if not all outputs, so knowing the Iq with outputs is important.

Standby mode
Vi = GND, IO = 0, 3.6 V 175 250 I/O = inputs, fscl = 0 kHz   (200uA)

Vi = VCC, IO = 0, 3.6 V 0.2 0.9 I/O = inputs, fscl = 0 kHz     (1uA)

please advise

  • Paul,

      Apologies for the delay . . .  Iq is specified only for inputs because of the current draw for the device on the I/O lines when set as inputs.  When oriented as outputs, the current draw on the I/O lines will be determined by the application, so it cannot be given as a set value.  

    The Icc will be the same during standby mode regardless of the I/O orientation.

    As far as a different device, could you send a block diagram or sketch of what is needed here, I'm not clear about the configuration, so before I recommend something, want to be sure I've got the application dentified.



  • As a follow-up to the difference in current for the two VI conditions. The reason for this is that there is an internal pull-up to Vi in the device. 

    During standby mode where Vi = Vcc, there is miniscule current (1uA) flowing due to the internal setup during standby mode. 

    Alternatively with Vi = GND, this resistor now acts as a pull-down and sinks current through the device to GND (200uA).