LTC4418 circuit

Hello,

We are using LTC4418 EVM circuit to switch between two power supplies in our LTE enodeB project.

https://www.analog.com/media/en/technical-documentation/eval-board-schematic/710-DC2707B_REV02_PCA_SCHEMATIC.pdf

The requirement is to switch between two 12V@5A DC inputs. One 12V@5A input is from DC Adapter for V1 of LTC4418, and the other input is from POE (power over ethernet) PD power supply module 12V@5A for V2. In the above circuit, we replicated the values of resistors same as channel V1 in channel V also as the Voltage values is same  that is ,12V. The components used are same as mentioned in the circuit. the optional (OPT) components are not mounted on our board. 

The problem is, When we connect one input, the voltage is available at the output of the mosfet, but it is not consistent. First, as the power is switched on, the voltage come up and goes low after few milliseconds and again comes up. We are using the output of LTC4418 as the input to TI, TPS65400 to generate Processor voltages like 1V, 1.8v, 0.85v etc, 

from this one of the voltage 1.8v is not stable, the 1.8v goes off.

Kindly advice whether the LTC4418 EVM works for 12V @ 7A. Any modification required to be taken care in the circuit. Kindly reply, We are in the Board bring up stage and struck in the Power Supply of LTC4418. 

Also how do we validate the reliability of the LTC4418 Circuit, as this may be an issue if the same occurs when it is deployed in the field.

Regards,

Sumathi