SLUSBL5A February 2015 – June 2019 UCC28730
The cable compensation pin is connected to a resistor to ground to program the amount of output voltage compensation needed to offset cable resistance. The cable compensation circuit generates a 0 to 3.13-V voltage level on the CBC pin corresponding to 0 A to IOCC maximum output current. The resistance selected on the CBC pin programs a current mirror that is summed into the VS feedback divider therefore increasing the regulation voltage as IOUT increases. There is an internal series resistance of 28 kΩ to the CBC pin which sets a maximum cable compensation for a 5-V output to approximately 400 mV when CBC is shorted to ground. The CBC resistance value can be determined using Equation 1.
Note that the cable compensation does not change the overvoltage protection (OVP) threshold, VOVP (see Electrical Characteristics), so the operating margin to OVP is less when cable compensation is used.