I am designing a 3s li-ion solar battery charger using the LTC 4079. The input voltage ranges from 3V to 19V. The typical charging voltage is 15-16V. The chip is programed to charge the batteries to 12.3V at 250mA. I currently am using a DFN adapter board for the LTC4079 with the rest of the related circuitry set up around it on prototyping board. The chip is getting hot and starts charging at 250mA and then reduces from there to around 180mA. It is having trouble maintaining the solar voltage when trying to regulate. Is the chip getting warm because a 16V input charging 12.3V @250mA too much for the chip or is the adapter causing the chip to overheat and designing a proper PCB should solve this problem?