PRODUCT DATASHEET
AAT2515
SystemPowerTM
Dual 600mA FastTransient High Frequency Buck Converter
Design Example
Specifications
VO1 = 2.5V @ 600mA (adjustable using 0.6V version), pulsed load ΔILOAD = 300mA
VO2 = 1.8V @ 600mA (adjustable using 0.6V version), pulsed load ΔILOAD = 300mA
VIN = 2.7V to 4.2V (3.6V nominal)
FS
= 1.4 MHz
TAMB = 85°C
2.5V VO1 Output Inductor
µs
µs
(see Table 1)
L1 = 3
⋅ VO1 = 3
⋅ 2.5V = 7.5µH
A
A
For Sumida inductor CDRH3D16, 10μH, DCR = 210mΩ.
⎛
⎞
= 72.3mA
VO1
VO1
2.5
V
2.5V
⎛
⎞
ΔI1 =
⋅ 1 -
⎝
=
⋅ 1 -
⎝
⎠
L1 ⋅ F
VIN
10μH ⋅ 1.4MHz
4.2V
⎠
ΔI1
= 0.6A + 0.036A = 0.64A
2
IPK1 = IO1
+
2
PL1 = IO1 ⋅ DCR = 0.6A2 ⋅ 210mΩ = 75.6mW
1.8V VO2 Output Inductor
µs
µs
(see Table 1)
L2 = 3
⋅ VO2 = 3
⋅ 1.8V = 5.4µH
A
A
For Sumida inductor CDRH3D16, 4.7μH, DCR = 105mΩ.
⎛
⎞
= 156mA
VO2
VO2
1.8
V
1.8V
⎛
⎞
⎠
ΔI2 =
⋅ 1 -
⎝
=
⋅ 1 -
⎝
⎠
L ⋅ F
VIN
4.7μH ⋅ 1.4MHz
4.2V
ΔI2
= 0.6A + 0.078A = 0.68A
2
IPK2 = IO2
+
2
PL2 = IO2 ⋅ DCR = 0.6A2 ⋅ 105mΩ = 37.8mW
w w w . a n a l o g i c t e c h . c o m
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2515.2007.12.1.0
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
