The adjustable version of the LM53625-Q1 and LM53635-Q1 devices regulates output voltage to a level that results in the FB node being VREF, which is approximately 1 V; seeElectrical Characteristics. Output voltage given a specific feedback divider can be calculated using Equation 3:
See Figure 54 for an example of the use of adjustable versions of the LM53625-Q1 and LM53635-Q1 devices. To ensure proper behavior for all modes of operation, a 50 kΩ resistor is recommended for RFBT. RFBB can then be determined using :
In addition a feed-forward capacitor CFF may be required to optimize the transient response. For output voltages greater than 6 V, the WEBENCH Design Tool can be used to optimize the design.