AAT2512
Dual 400mA High Frequency Buck Converter
Functional Block Diagram
FB1
VIN1
DH
Comp.
Err.
Amp.
LX1
Logic
Voltage
Reference
DL
Control
Logic
EN1
GND1
VIN2
See
Note
SGND1
FB2
DH
DL
Comp.
Err.
Amp.
LX2
Logic
Voltage
Reference
Control
Logic
EN2
GND2
See
Note
SGND2
Note: Internal resistor divider included for ≥1.2V versions. For low voltage versions, the feedback pin is tied directly to the error amplifier input.
The AAT2512 also features soft-start control to limit
inrush current. Soft start increases the inductor
Functional Description
current limit point in discrete steps when power is
The AAT2512 is a high performance power man-
applied to the input or when the enable pins are
agement IC comprised of two buck converters.
pulled high. It limits the current surge seen at the
Each channel has independent input voltages and
input and eliminates output voltage overshoot. The
enable/disable pins. Designed to operate at 1.4MHz
enable input, when pulled low, forces the converter
of switching frequency, the converters require only
into a low power, non-switching state consuming
three external components (CIN, COUT, and LX), min-
less than 1µA of current.
imizing cost and size of external components.
For overload conditions, the peak input current is
Both converters are designed to operate with an input
limited. As load impedance decreases and the out-
voltage range of 2.7V to 5.5V. Typical values of the
put voltage falls closer to zero, more power is dis-
output filter are 4.7µH and 4.7µF ceramic capacitor.
sipated internally, raising the device temperature.
The output voltage operates to as low as 0.6V and is
Thermal protection completely disables switching
offered as both fixed and adjustable. Power devices
when internal dissipation becomes excessive, pro-
are sized for 400mA current capability while main-
tecting the device from damage. The junction over-
taining over 90% efficiency at full load. Light load effi-
temperature threshold is 140°C with 15°C of hys-
ciency is maintained at greater than 80% down to
teresis. The under-voltage lockout guarantees suf-
500µA of load current. Both channels have excellent
ficient VIN bias and proper operation of all internal
transient response, load, and line regulation.
circuits prior to activation.
Transient response time is typically less than 20µs.
2512.2006.06.1.4
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ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
