APS1056 View Datasheet(PDF) - Advanced Analogic Technologies
Part Name
Description
MFG CO.
'APS1056' PDF : 20 Pages View PDF
APS1056
Fast Transient 600mA Step-Down Converter
Input Capacitor
Input Ripple VPP = 25mV
1
1
CIN = ⎛ VPP
⎝ IO
- ESR⎞⎠ · 4 · FS
=
⎛ 25mV
⎝ 0.6A
= 4.87µF; use 4.7µF
- 5mΩ⎞⎠ · 4 · 1.4MHz
IRMS =
IO
2
= 0.3Arms
P = esr · IRMS2 = 5mΩ · (0.3A)2 = 0.45mW
APS1056 Losses
PTOTAL
=
IO2
·
(RDSON(HS)
·
VO
+ RDSON(LS)
VIN
·
[VIN
-VO])
+ (tsw · F · IO + IQ) · VIN
0.62 · (0.725Ω · 1.8V + 0.7Ω · [4.2V - 1.8V])
=
4.2V
+ (5ns · 1.4MHz · 0.6A + 70µA) · 4.2V = 118mW
TJ(MAX) = TAMB + ΘJA · PLOSS = 85°C + (160°C/W) · 118mW = 103.9°C
APS1056.2007.04.0.9 (PRELIMINARY INFORMATION)
17
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