AAT1143IJS-2.5-T1 View Datasheet(PDF) - Advanced Analogic Technologies
Part Name
Description
MFG CO.
'AAT1143IJS-2.5-T1' PDF : 20 Pages View PDF
AAT1143
1MHz 400mA Step-Down Converter
Input Capacitor
Input Ripple VPP = 25mV
1
1
CIN =
⎛
⎝
VPP
IO
- ESR⎞⎠ · 4 · FS
=
⎛ 25mV
⎝ 0.4A
- 5mΩ⎞⎠ · 4 · 1MHz
= 4.75μF
IRMS =
IO
2
= 0.2Arms
P = esr · IRMS2 = 5mΩ · (0.2A)2 = 0.2mW
AAT1143 Losses
PTOTAL
=
IO2
·
(RDS(ON)H
·
VO
+ RDS(ON)L
VIN
·
[VIN
-VO])
+ (tsw · FS · IO + IQ) · VIN
0.42 · (0.725Ω · 1.8V + 0.7Ω · [4.2V - 1.8V])
=
4.2V
+ (5ns · 1.0MHz · 0.4A + 50μA) · 4.2V = 122mW
TJ(MAX) = TAMB + ΘJA · PLOSS = 85°C + (160°C/W) · 122mW = 104.5°C
16
1143.2006.07.1.10
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