Datasheet ADP2147 (Analog Devices)

Compact, 800 mA, 3 MHz, Simple DVS, Buck Regulator ADP2147 FEATURES GENERAL DESCRIPTION Input voltage: 2.3 V to 5.5 V
The ADP2147 is a high efficiency, low quiescent current, step-
Peak efficiency: 95%
down (buck) dc-to-dc regulator with an output voltage that can
3 MHz fixed frequency operation
be switched between two different settings under the control of
Low quiescent current: 23 μA
a select pin. The total solution requires only three tiny external
Ultralow shutdown current: 0.2 μA (typical)
components.
VSEL pin for simple dynamic voltage scaling (DVS)
The buck regulator automatically switches operating modes,
100% duty cycle low dropout mode
depending on the load current level, to maximize efficiency. At
Internal synchronous rectifier, compensation, and soft start
high output loads, the buck regulator operates in PWM mode.
Current overload and thermal shutdown protection
When the load current falls below a predefined threshold, the
Small, 6-ball, 1 mm × 1.5 mm WLCSP package
regulator operates in power save mode (PSM), improving the light-load efficiency.
APPLICATIONS
The ADP2147 runs on input voltages of 2.3 V to 5.5 V, which
PDAs and palmtop computers
allows for single lithium or lithium polymer cells, multiple
Wireless handsets
alkaline or NiMH cells, PCMCIA, USB, and other standard
Digital audio portable media players
power sources. The maximum load current of 800 mA is
Digital cameras, GPS navigation units
achievable across the input voltage range.
Low power portable medical equipment
The ADP2147 is available with fixed output voltages from 0.8 V to 3.3 V. All versions include an internal power switch and synchronous rectifier for minimal external part count and high efficiency. The ADP2147 has an internal soft start and is internally compensated. During logic controlled shutdown, the input is disconnected from the output, and the ADP2147 draws less than 0.2 μA (typical) from the power source. Other key features include undervoltage lockout to prevent deep battery discharge and soft start to prevent input current over- shoot at startup. The ADP2147 is available in a 6-ball WLCSP.
TYPICAL APPLICATIONS CIRCUIT 2.3V TO 5.5V 1.0µH VOUT VIN SW 4.7µF 4.7µF ADP2147 ON OFF EN VOUT VOUT_H V VSEL OUT_L GND
01 0 5- 88 09 Figure 1.
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Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION TYPICAL APPLICATIONS CIRCUIT TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS INPUT AND OUTPUT CAPACITOR, RECOMMENDED SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL DATA THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION CONTROL SCHEME PWM MODE POWER SAVE MODE Power Save Mode Current Threshold ENABLE/SHUTDOWN SIMPLE DYNAMIC VOLTAGE SCALING (DVS) SHORT-CIRCUIT PROTECTION UNDERVOLTAGE LOCKOUT THERMAL PROTECTION SOFT START CURRENT LIMIT 100% DUTY OPERATION APPLICATIONS INFORMATION EXTERNAL COMPONENT SELECTION Inductor Output Capacitor THERMAL CONSIDERATIONS PCB LAYOUT GUIDELINES EVALUATION BOARD EVALUATION BOARD LAYOUT OUTLINE DIMENSIONS ORDERING GUIDE