I have a prototyping PCB with 2 LDO's on it where one main LDO is running the board's CPU at 3.3V.
There's a second LDO (LT1129CS8) running at 6V to drive a 6V motor using a DRV8830 chip.
This LDO's SHDN pin is driven by the CPU's 3.3v pin to turn on/off the 6V power supply to the DRV8830. The idea was that this way we can get lower power consumption. The LDO should be at approximately 15uA when it's in shutdown.
Now, the problem is that when I turn off 6V power supply to the DRV8830, there seems to be a leaking current between SDA/SCL and GND of about 400uA.
For testing I have the DRV8830, a couple of capacitors and a 3.3V CPU on my breadboard. As soon as I connect SDA or SCL to the CPU I see the power consumption increase about 400uA. When I disconenct GND from the DRV8830 the power consumption is gone too.
Maybe this DRV8830 doesn't like power on it's SDA/SCL pin when there is no power on VCC?
But I'm not sure how I can fix this and get the low power consumption that I was planning ...
There's a second LDO (LT1129CS8) running at 6V to drive a 6V motor using a DRV8830 chip.
This LDO's SHDN pin is driven by the CPU's 3.3v pin to turn on/off the 6V power supply to the DRV8830. The idea was that this way we can get lower power consumption. The LDO should be at approximately 15uA when it's in shutdown.
Now, the problem is that when I turn off 6V power supply to the DRV8830, there seems to be a leaking current between SDA/SCL and GND of about 400uA.
For testing I have the DRV8830, a couple of capacitors and a 3.3V CPU on my breadboard. As soon as I connect SDA or SCL to the CPU I see the power consumption increase about 400uA. When I disconenct GND from the DRV8830 the power consumption is gone too.
Maybe this DRV8830 doesn't like power on it's SDA/SCL pin when there is no power on VCC?
But I'm not sure how I can fix this and get the low power consumption that I was planning ...
