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AAT2689 Datasheet, PDF (18/20 Pages) Advanced Analogic Technologies – PMIC Solution for 12V Adapter Systems with 2-Output High Performance Step-Down Converters
DATA SHEET
AAT2689
PMIC Solution for 12V Adapter Systems
with 2-Output High Performance Step-Down Converters
Channel 1 Current Limit
Voltage sense VS = 100mV
Total trace parasitic resistor and inductor DCR is 10m
ILIM =
VS =
DCR
100mV
10mΩ
= 10A > 5A
R8 =
VOUT1 · R2
=
VOCP - ILIMIT · DCR
3.3V · 2kΩ = 133kΩ
0.1V - 5A · 10mΩ
R7 =
R2 · R8
R8 - R2
=
2kΩ · 133kΩ
133kΩ - 2kΩ
= 2kΩ
AAT2689 Losses
All values assume a 25°C ambient temperature and thermal resistance of 50°C/W in the TDFN34-16 package.
PTOTAL = IOUT12 · RDS(ON)H · D + (tSW · FS · IOUT1 + IQ1) · VIN1 + (VIN2 - VOUT2) · IOUT2
PTOTAL = 2.5A2 · 70mΩ · 3.3V + (5ns · 490kHz · 2.5A + 70μA) · 12V · (3.3V - 1.8V) · 600mA
12V
PTOTAL = 1.1W
TJ(MAX) = TAMB + ΘJA · PLOSS = 25°C + (50°C/W) · 1.1W = 80°C
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202035A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 8, 2012