AAT2315_07 Datasheet, PDF (16/22 Pages) Advanced Analogic Technologies – Dual 600mA Step-Down Converter with Synchronization

AAT2513
Dual 600mA Step-Down
Converter with Synchronization
Design Example
Specifications
V_O1 2.5V @ 600mA (adjustable using 0.6V version), pulsed load ΔI_LOAD = 300mA
V_O2 1.8V @ 600mA (adjustable using 0.6V version), pulsed load ΔI_LOAD = 300mA
V_IN 2.7V to 4.2V (3.6V nominal)
F_S
1.7 MHz
T_AMB 85°C
1.8V V_O1 Output Inductor
µs
µs
L1 = 1.2 _A ⋅ V_O1 = 1.2 _A ⋅ 1.8V = 2.2µH
(see table 1).
For Sumida CDRH2D11 2.2µH DCR = 98mΩ.
ΔI1 =
V_O1
L⋅F
⋅
⎛⎝₁
-
V_O1 ⎞
V_IN ⎠
=
2.5V
3.3µH ⋅ 1.7MHz
⋅
⎛
⎝^{1 -}
2.5V⎞
4.2V⎠
=
230mA
I_PK1
=
I_O1
+
ΔI1
2
=
0.4A
+
0.115A
=
0.515A
P_L1 = I_O12 ⋅ DCR = 0.6A² ⋅ 123mΩ = 44mW
2.5V V_O2 Output Inductor
µs
µs
L1 = 1.2 _A ⋅ V_O1 = 1.2 _A ⋅ 2.5V = 3.3µH
(see table 1).
For Sumida inductor CDRH2D11 3.3µH DCR = 123mΩ.
ΔI2 =
V_O2
L⋅F
⋅
⎛⎝₁
-
V_O2 ⎞
V_IN ⎠
=
2.5V
3.3µH ⋅ 1.7MHz
⋅
⎛
⎝^{1 -}
2.5V⎞
4.2V⎠
=
230mA
I_PK2
=
I_O2
+
ΔI2
2
=
0.4A
+
0.115A
=
0.515A
P_L2 = I_O22 ⋅ DCR = 0.6A² ⋅ 123mΩ = 44mW
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