AAT1143IJS-0.6-T1 AnalogicTech, AAT1143IJS-0.6-T1 Datasheet - Page 15

• Manufacturer Part Number: AAT1143IJS-0.6-T1
• Description: 1MHz 400mA Step-Down Converter
• Manufacturer: AnalogicTech

Step-Down Converter Design Example
Specifications
V
V
F
T
1.8V Output Inductor
L1 = 3
For Sumida inductor CDRH3D16, 4.7μH, DCR = 105mΩ.
ΔI
1.8V Output Capacitor
V
C
I
Input Capacitor
Input Ripple V
C
I
P = esr · I
P
P
SwitchReg
SwitchReg
I
1143.2009.02.1.11
1143.2009.02.1.11
RMS
RMS
PKL1
S
AMB
O
IN
L1
DROOP
OUT
esr
IN
L1
= 1.0MHz
= 1.8V @ 400mA (adjustable using 0.6V version), Pulsed Load ΔI
= 2.7V to 4.2V (3.6V nominal)
=
= I
= esr · I
=
=
=
= 85°C
= I
=
⎛
⎝
O
I
μsec
2
2
= 0.2V
V
L1 ⋅ F
O
O
2
V
3 · ΔI
·
A
DROOP
I
1
⋅ DCR = 0.4A
+
O
PP
V
= 0.2Arms
RMS
3
O
ΔI
RMS
2
- ESR · 4 · F
·
⋅ V
2
S
LOAD
L1
(V
= 5mΩ · (0.2A)
· F
2
TM
TM
PP
⋅ 1 -
= 0.4A + 0.11A = 0.51A
O2
= 5mΩ · (63mA)
O
L1 · F
⎛
⎝
S
) · (V
= 25mV
1
= 3
⎞
⎠
=
V
V
0.2V · 1MHz
S
μsec
IN(MAX)
O
IN
2
· V
A
3 · 0.3A
⎞
⎠
⋅ 105mΩ = 17mW
S
=
IN(MAX)
=
⋅ 1.8V = 5.4μH
- V
4.7μH ⋅ 1.0MHz
2
⎛
⎝
O
= 0.2mW
)
2
25mV
1.8 V
0.4A
= 20μW
=
= 4.5μF
2
·
1
3
- 5mΩ · 4 · 1MHz
·
4.7μH · 1.0MHz · 4.2V
(see Table 1)
1.8V · (4.2V - 1.8V)
1
⋅ 1 -
⎞
⎠
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
⎛
⎝
1.8V
4.2V
⎞
⎠
= 218mA
= 4.75μF
= 63mArms
LOAD
1MHz 400mA Step-Down Converter
1MHz 400mA Step-Down Converter
= 300mA
PRODUCT DATASHEET
PRODUCT DATASHEET
AAT1143
AAT1143
15
15