AAT1121 Datasheet, PDF (16/19 Pages) Advanced Analogic Technologies – 1.5MHz, 250mA Step-Down Converter

AAT1121 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
AAT1121
1.5MHz, 250mA Step-Down Converter
0.2² · (0.59Ω · 1.8V + 0.42Ω · [4.2V - 1.8V])
=
4.2V
+ (5ns · 1.5MHz · 0.2A + 30µA) · 4.2V = 26.14mW
T_J(MAX) = T_AMB + Θ_JA · P_LOSS = 85°C + (50°C/W) · 26.14mW = 86.3°C
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16
201974B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 15, 2013