Datasheet
Application information PM8903A
22/33 Doc ID 024147 Rev 1
Electrolytic capacitors have a large capacitance to minimize voltage deviation during load
transients while they do not show the same ESR values as the MLCC, resulting then in
higher ripple voltages.
A mix between an electrolytic and MLCC capacitor can be used to minimize ripple as well as
reducing voltage deviation in dynamic mode.
The high bandwidth error amplifier of the PM8903A and external compensation enables a
wide range of output filter configurations (including all MLCC solutions) and fast transient
response.
6.5 Input capacitors
The input capacitor bank is designed considering, mainly, the input RMS current that
depends on the output deliverable current (I
OUT
) and the duty-cycle (D) for the regulation as
follows:
The equation reaches its maximum value, I
OUT
/2, with D = 0.5. The losses depend on the
input capacitor ESR and, in the worst case, are:
I
rms
I
OUT
D1D–()⋅⋅=
PESRI
OUT
2⁄()
2
⋅=