JAJSKQ3D February 2016 – December 2022 LM5165
PRODUCTION DATA
Three voltage feedback options are available: the fixed 3.3-V and 5-V versions include internal feedback resistors that sense the output directly through the VOUT pin; the adjustable voltage option senses the output through an external resistor divider connected from the output to the FB pin.
The LM5165 voltage regulation loop regulates the output voltage by maintaining the FB voltage equal to the internal reference voltage, VREF1. A resistor divider programs the ratio from output voltage VOUT to FB. For a target VOUT setpoint, calculate RFB2 based on the selected RFB1 using Equation 5.
Selecting RFB1 in the range of 100 kΩ to 1 MΩ is recommended for most applications. A larger RFB1 consumes less DC current, which is mandatory if light-load efficiency is critical. However, RFB1 larger than 1 MΩ is not recommended as the feedback path becomes more susceptible to noise. High feedback resistances generally require more careful feedback path PCB layout. It is important to route the feedback trace away from the noisy area of the PCB. For more layout recommendations, see Layout.