AAT1184 Datasheet, PDF (17/18 Pages) Advanced Analogic Technologies – High Voltage Step-Down Regulator

Current Limit
Over-Current Offset Voltage: V_OCP = 100mV
Total trace parasitic resistor and inductor DCR is 30m
I_LIMIT = 3A
I_PRESET =
V_OCP
DCR
=
100mV
30mΩ
= 3.3A
DATA SHEET
AAT1184
High Voltage Step-Down Regulator
AAT1184 Losses
All values assume an 85°C ambient temperature and thermal resistance of 50°C/W in the TSOPJW-12 package.
P_TOTAL = I_OUT2 · R_DS(ON)H · D + (t_SW · F_S · I_OUT + I_Q) · V_IN
P_TOTAL = ^{1.2A2 · 70mΩ · 5V} + (5ns · 490kHz · 1.2A + 70µA) · 12V
12V
P_TOTAL = 78mW
T_J(MAX) = T_AMB + Θ_JA · P_LOSS = 85°C + (140°C/W) · 78mW = 96°C
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