sm72485sdx National Semiconductor Corporation, sm72485sdx Datasheet - Page 12

• Manufacturer Part Number: sm72485sdx
• Description: Solarmagic 100v, 150 Ma Constant On-time Buck Switching Regulator
• Manufacturer: National Semiconductor Corporation

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LOW OUTPUT RIPPLE CONFIGURATIONS
For applications where low output ripple is required, the fol-
lowing options can be used to reduce or nearly eliminate the
ripple.
a) Reduced ripple configuration: In
across R
pin. This allows the ripple at V
of 25 mVp-p by reducing R3, since the ripple at V
attenuated by the feedback resistors. The minimum value for
Cff is determined from:
FB2
to AC-couple the ripple at V
OUT
to be reduced to a minimum
Figure
FIGURE 5. Efficiency vs. Load Current and V
OUT
directly to the FB
7, Cff is added
FIGURE 6. Efficiency vs. V
OUT
is not
12
where t
(min)
for Cff.
. The next larger standard value capacitor should be used
ON(max)
IN
is the maximum on-time, which occurs at V
30142324
30142328
IN
IN