PCA9546A: PCA9546A #RESET pin

Hi Peter,

I would just like to double check something real quick. The RESET pin on the PCA9546A is active low, so in your current set up you would like to reset this device every time another device on your board is enabled? This is totally fine just make sure that the voltages of that EN pin match up with the VIH and VIL of the RESET pin. There is also an Errata on this device where if the RESET pin has a higher voltage than VCC, current will flow from RESET to VCC. So make sure that the voltage of RESET is less than or equal to VCC.

There is no maximum pulse duration for the RESET pin, there is only a minimum requirement. You can hold this device in RESET indefinitely. As long as you operate within the Absolute Maximum Ratings of the device you can't do any permanent damage.

I will check to see if we have data on the supply current when RESET is held low.

Best,

Chris

Hi Chris,

Thanks for getting back to me.

Actually, the EN pins on the other devices are active high, so the intention would be to hold the PCA9546A in reset all the time the other devices are disabled, and bring it out of reset at the same time as the other devices are enabled (when the EN line goes high).

The points you've raised don't sound like they should be a problem to me - thanks for that, but would certainly welcome any data you have on current consumption. 

All the best,

Peter

Hi Peter,

So actually looking at the datasheet I found that the we do have a rating for the input current on the reset pin.

We don't have a measurement on how ICC changes when reset is held low.

Best,

Chris

Hi Chris,

Yes, unfortunately it was the change in Icc I wanted.

I guess I'll have to make my own measurements?

Thanks,

Peter