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 1608A1.
U2 on the iPhone 5
U5900 on the iPad 4
U1300 on the iPad Mini 1
Please do not substitute a different IC model in place of this chip. You will not be happy with the results!