JAJSFS7B July 2018 – February 2019 LM5180-Q1
ADVANCE INFORMATION for pre-production products; subject to change without notice.
The LM5180-Q1 employs a unique thermal compensation circuit that adjusts the feedback setpoint based on the thermal coefficient of the flyback diode's forward voltage drop. Even though the output voltage is measured when the secondary current is effectively zero, there is still a non-zero forward voltage drop associated with the flyback diode. Select the thermal compensation resistor using Equation 9.
The temperature coefficient of the diode voltage drop may not be explicitly provided in the diode datasheet, so the effective value can be estimated based on the measured output voltage shift over temperature when the TC resistor is not installed.