AAT2550_08 ANALOGICTECH [Advanced Analogic Technologies], AAT2550_08 Datasheet - Page 31

• Manufacturer Part Number: AAT2550_08
• Description: Total Power Solution for Portable Applications
• Manufacturer: ANALOGICTECH [Advanced Analogic Technologies]

SystemPower
SystemPower
Step-Down Converter Design Example
Specifications
V
V
V
F
T
2.5V V
L1 = 3
For Sumida inductor CDRH2D14, 6.8μH, DCR = 170mΩ.
P
1.8V V
L2 = 3
For Sumida inductor CDRH2D14, 4.7μH, DCR = 135mΩ.
ΔIB =
P
2550.2008.02.1.3
2550.2008.02.1.3
ΔIA =
I
I
PKA
PKB
S
AMB
OA
OB
IN
LA
LB
= I
= I
= 2.5V @ 400mA (V
= 1.8V @ 400mA (V
= 2.7V to 4.2V (3.6V nominal)
= 1.4MHz
= 85°C
= I
= I
L ⋅ F
L1 ⋅ F
OA
OB
μsec
OA
μsec
V
OB
OB
A
2
A
2
V
OA
OB
+
+
⋅ DCR = 0.45
⋅ DCR = 0.4A
O
S
ΔIA
ΔIB
S
⋅ 1 -
Output Inductor
2
Output Inductor
2
⋅ V
⋅ V
⎛
⎝
⋅ 1 -
⎛
⎝
O1
O2
= 0.4A + 0.053A = 0.453A
= 0.4A + 0.078A = 0.48A
V
V
= 3
= 3
TM
TM
OB
IN
V
V
⎞
⎠
OA
IN
μsec
μsec
⎞
⎠
2
=
A
A
2
=
⋅ 170mΩ = 34mW
4.7μH ⋅ 1.4MHz
⋅ 135mΩ = 21.6mW
FBA
FBB
6.8μH ⋅ 1.4MHz
⋅ 2.5V = 7.5μH
⋅ 1.8V = 5.4μH
= 0.6V), pulsed load ΔI
= 0.6V), pulsed load ΔI
1.8 V
2.5 V
⋅ 1 -
⎛
⎝
(see Table 5)
(see Table 5)
⋅ 1 -
⎛
⎝
1.8V
4.2V
w w w . a n a l o g i c t e c h . c o m
w w w . a n a l o g i c t e c h . c o m
4.2V
2.5V
⎞
⎠
LOAD
LOAD
⎞
⎠
= 156mA
= 106mA
= 300mA
= 300mA
Total Power Solution for Portable Applications
Total Power Solution for Portable Applications
PRODUCT DATASHEET
PRODUCT DATASHEET
AAT2550178
AAT2550178
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