Supply Current of MAX22445 when EN pin is Inactive

Hi Ken, 

The EN pin disables the output buffers on that side. This will remove the switching losses associated with parasitic capacitance of the output traces. In terms of current the power supply no longer needs to provide the i=c*V*f to drive the PCB trace.

There would be no change on the input side of the channel when the output side is disabled.

Regards,

Jason 

Hi Jason,

Thanks for the reply!

What I'm really interested in knowing is the current consumption of the IC at that specific side (say side B) when EN is inactive (ENB is pulled low).

In my application, I have a relay switching the VDDB and GND from following my Device's digital supplies to a fixed one. This would isolate my device from the MAX22445.

Switching this relay would ultimately cause hot switching and I would like to know how much current is being drawn when VDDB wrt GNDB is 5V when ENB is inactive.

The spectable shows supplies currents up to 6.8mA at 50MHz and 1.8mA at 500kHz, but no indication what the current would be when there's no signal or ENB is inactive.

I have some passive components to mitigate this hot-switching, and some software routines could help, but knowing this current would greatly help me in choosing the right components for my design right now.

Regards,

Ken

Hi Ken, 

Figure 9 and Figure 10 of the MAX22445 datasheet show typical idle current requirements. There is also the Calculating Power Dissipation section of the datasheet that goes into detail about power consumption estimates. 

In the circuit above, the same voltage domains are on both sides of the isolator. Such a configuration will not provide galvanic isolation. Neither the voltage domains or signals can be shorted across the barrier if the intention is to have galvanic isolation. 

Regards,

Jason

Found it!

Thanks, Jason.

I understand the concern on the circuit, the intent here is to actually have the signals of sideB follow my device's digital levels when I try to move VL and GND wrt to AGND. This would allow me to still communicate with the part even when my Device's GND is shifted from AGND in some of my applications.

Regards,

Ken

Found it!

Thanks, Jason.

I understand the concern on the circuit, the intent here is to actually have the signals of sideB follow my device's digital levels when I try to move VL and GND wrt to AGND. This would allow me to still communicate with the part even when my Device's GND is shifted from AGND in some of my applications.

Regards,

Ken