ADP5020 Analog Devices, ADP5020 Datasheet - Page 22

• Manufacturer Part Number: ADP5020
• Description: Power Management Unit for Imaging Modules
• Manufacturer: Analog Devices

ADP5020
LDO INPUT FILTER
To improve the LDO input-to-output ripple suppression in the
critical switching frequency range of the buck converters, it may be
necessary to add an LC filter tuned to 1 MHz, as shown in
Figure 28. Additional tests and simulation must be performed
to assess if this filter is necessary.
The filter resonance frequency is determined by the following
equation:
where L3 = 250 nH, assuming that f
The inductor must be able to withstand the LDO load current,
including the overload condition, which is limited to 400 mA.
f
LC
=
2
×
π
×
1
L3
×
C8
LC
= 1 MHz and C8 = 100 nF.
Rev. 0 | Page 22 of 28
(3)
VBATT
10µF
C1
Figure 28. Optional LDO Input Filter
ADP5020
BUCK 1
LDO
VOUT1
VOUT1
VDD3
VOUT3
10µF
SW1
C6
1µF
C3
L1
2.2µH
0.1µF
L3
C8
3.3V
2.8V
INPUT FILTER
LDO