AAT1185 Datasheet, PDF (15/16 Pages) Skyworks Solutions Inc. – High Voltage Step-Down Controller

DATA SHEET
AAT1185
High Voltage Step-Down Controller
Current Limit
Over-current offset voltage V_OCP = 100mV
Total trace parasitic resistor and inductor DCR is 6m
I_LIMIT =
V_{S =}
DCR
100mV
6mΩ
= 17A
In order to sense the inductor current correctly during dynamic operation the R-C network time constant R3 *C9 should
match the inductor time constant L1/DCR:
L₁
DCR
= R₃ · C₉
Choose C3 = 0.47μF
R₃
=
L₁
DCR ·
C₉
=
3.9μH
4.8mΩ · 0.47μF
=
1.74kΩ
AAT1185 Losses
All values assume 25°C ambient temperature and thermal resistance of 140°C/W in the TSOPJW-12 package.
P_TOTAL = (t_SW · F_S · I_OUT1 + I_Q) · V_IN
P_TOTAL = (5ns · 490kHz · 10A + 70μA) · 12V
P_TOTAL = 295mW
T_J(MAX) = T_AMB + Θ_JA · P_LOSS = 85°C + (140°C/W) · 0.295mW = 126.3°C
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
202001A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 31, 2012
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