AP6015 Diodes, Inc., AP6015 Datasheet - Page 15

• Manufacturer Part Number: AP6015
• Description: High Efficiency Step-down Low Power Dc-dc Converter
• Manufacturer: Diodes, Inc.

Application Information
Though there is no special requirement for the ESR (Equivalent Series Resistance) of the input capacitor, due
attention should be paid to the tolerance and temperature coefficient of the capacitor used. A 10uF or larger
capacitance is required between the PVCC and the GND pins. The input capacitor should be placed as
close as possible to the PVCC pin in order to achieve good overall system performance.
Ripple at the voltage output pin is caused by the charge-and-discharge of the output capacitor. For the best
performance, a low ESR output capacitor should be used. The equation below demonstrates how the size of
the ripple can be calculated.
Where:
△Vo= Output voltage ripple
L = Inductor value
f = Switching frequency (1MHz typical)
△I
AP6015 Rev. 3
Δ
V
L
O
= Peak-to-peak inductor ripple current
Input Capacitor Selection
Output Capacitor Selection
=
V
O
×
1
−
L
(
×
V
V
CC
f
O
)
×
(
8
×
C
1
O
×
High Efficiency Step-Down Low Power DC-DC Converter
f
(Continued)
+
ESR
www.diodes.com
)
=
15 of 18
Δ
I
L
×
(
8
×
C
1
O
×
f
+
ESR
)
©
FEBRUARY 2009
AP6015
Diodes Incorporated