600 mA/1000 mA, 2.5 MHz Buck-Boost
1 mm height profile
Compact PCB footprint
Seamless transition between modes
38 μA typical quiescent current
2.5 MHz operation enables 1.5 μH inductor
Input voltage: 2.3 V to 5.5 V
Fixed output voltage: 2.8 V to 5.0 V
Adjustable model output voltage range: 2.8 V to 5.5 V
600 mA (ADP2503) and 1000 mA (ADP2504) output options
Boost converter configuration with load disconnect
SYNC pin with three different modes
Power save mode (PSM) for improved light load efficiency
Forced fixed frequency operation mode
Synchronization with external clock
Enable/shutdown logic input
Undervoltage lockout protection
Small 10-lead 3 mm × 3 mm LFCSP (QFN) package
Supported by ADIsimPower™ design tool
Digital cameras/portable audio players
Miniature hard disk power supplies
USB powered devices
The ADP2503/ADP2504 are high efficiency, low quiescent current
step-up/step-down dc-to-dc converters that can operate at input
voltages greater than, less than, or equal to the regulated output
voltage. The power switches and synchronous rectifiers are
internal to minimize external device count. At high load currents,
the ADP2503/ADP2504 use a current-mode, fixed frequency
pulse-width modulation (PWM) control scheme for optimal
stability and transient response. To ensure the longest battery life
in portable applications, the ADP2503/ADP2504 have an optional
power save mode that reduces the switching frequency under
light load conditions. For wireless and other low noise applica-
tions where variable frequency power save mode may cause
interference, the logic control input sync forces fixed frequency
PWM operation under all load conditions.
The ADP2503/ADP2504 can run from input voltages between
2.3 V and 5.5 V, allowing single lithium or lithium polymer cell,
multiple alkaline or NiMH cells, PCMCIA, USB, and other stan-
dard power sources. The ADP2503/ADP2504 have fixed output
options, or using the adjustable model, the output voltage can
be programmed through an external resistor divider. Compensa-
tion is internal to minimize the number of external components.
During logic-controlled shutdown, the input is disconnected
from the output and draws less than 1 μA from the input source.
Operating as boost converters, the ADP2503/ADP2504 feature a
true load disconnect function that isolates the load from the
power source. Other key features include undervoltage lockout
to prevent deep battery discharge, and soft start to prevent input
current overshoot at startup.
TYPICAL APPLICATION CIRCUIT
2.3V TO 5.5V
2.8V TO 5V
EN AGND PGND
1ALLOWS THE ADP2503/ADP2504 TO OPERATE IN
THREE DIFFERENT MODES.
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