Other Parts Discussed in Thread: TPS54J061, TPS548A28
I am trying to reduce the output voltage ripple on our TPS548B27 design.
According to the datasheet, with VIN = 4.5 – 5.5V, IOUT = 2.5A, VOUT = 1.03V, and fSW = 800 kHz, the inductor should be:
LMIN = 1.046 uH
LMAX = 2.790 uH
Yet, Webench(R) Power Designer chooses 174.398 nH for the inductor for these same input parameters. This causes the inductor ripple current to be 6A, when IOUT is only 2.5A. This results in a negative ILIM_VALLEY calculation.
Currently, our design is using a 330nH inductor and 366.8uF of output capacitance. This results in too much output voltage ripple.
I would like help in understanding what I need to change in order to reduce the output voltage ripple of this power supply.
Regards,
Jeff K