This Tristar IC talks to the charger before allowing it to charge the phone, and often causes slow charging, no charging, or death after being plugged into a fake charger. NXP 1610A2. U1700 on the iPh..
This IC allows the touchscreen to communicate with the phone. U2401 in the iPhone 6 and 6+U12 in the iPhone 5, 5C, and 5SU6600/U6650 in the iPad AirU4100/U4150 in the iPad Air 2U4301 in the iPhone SET..