ZHCSN09A June 2021 – September 2022 LM5168-Q1 , LM5169-Q1
PRODUCTION DATA
The LM516x-Q1 voltage regulation loop regulates the output voltage by maintaining the FB voltage equal to the internal reference voltage, VREF = 1.2 V (typical). A resistor divider programs the ratio from the output voltage VOUT1 to VREF.
Equation 29 is used to calculate RFBT based on a selected RFBB.
TI recommends selecting RFBB in the range of 10 kΩ to 1 M? for most applications. A larger RFBB consumes less DC current, which is mandatory if light-load efficiency is critical. TI does not recommend RFBB larger than 1 MΩ as the feedback path becomes more susceptible to noise. For this example, RFBB = 61.9 kΩ is chosen. This action gives RFBT = 453 kΩ. Route the feedback trace away from the noisy area of the PCB and keep the feedback resistors close to the FB pin.