PRODUCT DATASHEET
AAT2550178
SystemPowerTM
Total Power Solution for Portable Applications
2.5V Output Capacitor
3 · ΔILOAD
VDROOP · FS
3 · 0.3A
COUT
=
=
= 3.2μF
0.2V · 1.4MHz
(VOUT) · (VIN(MAX) - VOUT
)
1
2.5V · (4.2V - 2.5V)
1
·
= 21mArms
IRMS(MAX)
=
·
=
10μH · 1.4MHz · 4.2V
L · FS · VIN(MAX)
2· 3
2· 3
Pesr = esr · IRMS2 = 5mΩ · (21mA)2 = 2.2μW
1.8V Output Capacitor
3 · ΔILOAD
VDROOP · FS
3 · 0.3A
COUT
=
=
= 3.2μF
0.2V · 1.4MHz
(VOUT) · (VIN(MAX) - VOUT
)
1
1.8V · (4.2V - 1.8V)
1
·
= 45mArms
IRMS(MAX)
=
·
=
4.7μH · 1.4MHz · 4.2V
L · FS · VIN(MAX)
2· 3
2· 3
Pesr = esr · IRMS2 = 5mΩ · (45mA)2 = 10μW
Input Capacitor
Input Ripple VPP = 25mV.
1
1
CIN =
=
= 6.8μF
⎛
VPP
⎞
⎠
⎛ 25mV
⎝ 0.8A
⎞
⎠
- ESR · 4 · FS
- 5mΩ · 4 · 1.4MHz
⎝IO1 + IO2
IO1 + IO2
IRMS(MAX)
=
= 0.4Arms
2
P = esr · IRMS2 = 5mΩ · (0.4A)2 = 0.8mW
w w w . a n a l o g i c t e c h . c o m
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2550.2008.02.1.3
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
