AAT1152IKS-1.2-T1 View Datasheet(PDF) - Analog Technology Inc
Part Name
Description
MFG CO.
'AAT1152IKS-1.2-T1' PDF : 18 Pages View PDF
AAT1152
850kHz 1A Synchronous Buck DC/DC Converter
Inductor Selection:
L
=
VOUT
IO ⋅ k ⋅
F
⋅
1
-
VOUT
VIN
=1.0A
⋅
1.5V
0.3 ⋅
830kHz
⋅
1
-
1.5V
4.2V
=
3.9µH
Select Sumida inductor CDRH5D18 4.1µH 57mΩ 2.0 mm height.
∆I =
VO
L⋅F
⋅
1
-
VO
VIN
=
1.5V
4.1µH ⋅ 830kHz
⋅
1-
1.5V
4.2V
= 280mA
IPK
=
IOUT
+
∆I
2
=
1.0A
+
0.14A
=
1.14A
P = IO2 ⋅ DCR =57mW
Output Capacitor Dissipation:
IRMS
=
1
2⋅
3⋅
VOUT ⋅ (VIN
L⋅F⋅
- VOUT)
VIN
=
1
2⋅
3
⋅
1.5V
4.1µH
⋅
⋅
(4.2V - 1.5V)
830kHz ⋅ 4.2V
=82mARMS
PESR = ESRCOUT ⋅ IRMS2 = 5mΩ ⋅ .0822 A = 33µW
AAT1152 Dissipation:
P
=
IO2
·
(RDSON(H)
·
VO +
VIN
RDSON(L)
·
(VIN
-VO))
+ (tsw · F · IO + IQ) · VIN
=
(0.14Ω
·
1.5V
+ 0.145Ω
3.6V
·
(3.6V
-
1.5V))
+
(20nsec
·
830kHz
·
1.0A
+
0.3mA)
·
3.6V
=
0.203W
TJ(MAX) = TAMB + ΘJA · PLOSS = 85°C + 150°C/W · 0.203W = 115°C
1152.2003.01.0.9
15
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