AAT1146 Datasheet, PDF (17/20 Pages) Advanced Analogic Technologies – Fast Transient 400mA Step-Down Converter

AAT1146 Losses
P_TOTAL
=
I_O2
·
(R_DSON(HS)
·
V_O
+ R_DSON(LS)
V_IN
·
[V_IN
-V_O])
+ (t_sw · F · I_O + I_Q) · V_IN
DATA SHEET
AAT1146
Fast Transient 400mA Step-Down Converter
0.4² · (0.725Ω · 1.8V + 0.7Ω · [4.2V - 1.8V])
=
4.2V
+ (5ns · 1.4MHz · 0.4A + 70μA) · 4.2V = 126mW
T_J(MAX) = T_AMB + Θ_JA · P_LOSS = 85°C + (160°C/W) · 126mW = 105.1°C
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
201985B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
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