I have designed a 5V SEPIC circuit for the TPS55340 and received my PCB. After assembly I am having issues with the disabled state of the TPS55340 chip. It works file when enabled and successfully gives me a steady 5V output with the required current capacity.
However, when I pull the EN line low (initially with a MCU but later by directly shorting to GND) the chip seems to turn off initially and the current consumption is low (~20uA) but then after a few seconds it beings to rise and continues to rise and jump around with anywhere between the 20uA level and several mA. It is almost like the chip is becoming re-enabled and then discovering it is supposed to be off and turning off again causing the current to jump unpredictably.
This is very problematic for me as we are trying to use this board in an ultra low power application so we are counting micro-amps. 2mA is going to absolutely kill my lifespan, so I need to resolve this.
Attached are my schematic for this section as well as images of the layout. The circuit is located on the Bottom layer, but I included all layers as a reference and because there are a couple signals that jump layers.
What could be causing this unstable and high disabled state?
