PRODUCT DATASHEET
AAT2515
SystemPowerTM
Dual 600mA FastTransient High Frequency Buck Converter
Functional Block Diagram
FB1
VIN1
DH
DL
Comp.
Err.
Amp.
LX1
Logic
Voltage
Reference
Control
Logic
EN1
GND
VIN2
See
Note
GND
DH
DL
Comp.
FB2
EN2
Err.
Amp.
LX2
Logic
Voltage
Reference
Control
Logic
GND
See
Note
GND
Note: Internal resistor divider included for fixed output voltage versions. For low voltage versions, the feedback pin is tied directly to the error amplifier input.
The AAT2515 also features soft-start control to limit
Functional Description
inrush current. Soft start increases the inductor current
The AAT2515 is a high performance power management
limit point in discrete steps when power is applied to the
IC comprised of two buck converters. Each channel has
input or when the enable pins are pulled high. It limits
independent input voltages and enable pins. Designed to
the current surge seen at the input and eliminates out-
operate at 1.4MHz of switching frequency, the converters
put voltage overshoot. The enable input, when pulled
require only three external components (CIN, COUT, and
low, forces the converter into a low power, non-switching
LX), minimizing cost and size of external components.
state consuming less than 1μA of current.
Both converters are designed to operate with an input
For overload conditions, the peak input current is limit-
voltage range of 2.7V to 5.5V. Typical values of the out-
ed. As load impedance decreases and the output voltage
put filter are 4.7μH and 10μF ceramic capacitor. The
falls closer to zero, more power is dissipated internally,
output voltage operates to as low as 0.6V and is offered
raising the device temperature. Thermal protection com-
as both fixed and adjustable. Power devices are sized for
pletely disables switching when internal dissipation
600mA current capability while maintaining over 90%
becomes excessive, protecting the device from damage.
efficiency at full load. Light load efficiency is maintained
The junction over-temperature threshold is 140°C with
at greater than 80% down to 500μA of load current.
15°C of hysteresis. The under-voltage lockout guaran-
Both channels have excellent transient response, load,
tees sufficient VIN bias and proper operation of all inter-
and line regulation. Transient response time is typically
nal circuits prior to activation.
less than 20μs.
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2515.2007.12.1.0
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ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
