SWCS134A October 2017 – February 2025 TPS6508700
PRODUCTION DATA
Placement of an inductor between the external FETs and the output capacitors is required. Together, the inductor and output capacitors form a double pole in the control loop that contributes to stability. Additionally, the inductor is directly responsible for the output ripple, efficiency, and transient performance. As the inductance used increases, the ripple current decreases, which typically results in an increase in efficiency. However, with an increase in inductance used, the transient performance decreases. Finally, the inductor selected must be rated for appropriate saturation current, core losses, and DCR.
Internal parameters for the converters are optimized for a 0.47-µH inductor for BUCK3 and a 1-µH inductor for BUCK4 and BUCK5; however, using other inductor values is possible as long as they are chosen carefully and thoroughly tested.

With the chosen inductance value and the peak current for the inductor in steady state operation, IL(MAX) can be calculated using Equation 9. The rated saturation current of the inductor must be higher than the IL(MAX) current.
