Datasheet ADP2102 (Analog Devices)

Low Duty Cycle, 600 mA, 3 MHz, Synchronous Step-Down DC-to-DC Converter Data Sheet ADP2102 FEATURES TYPICAL APPLICATION CIRCUIT Input voltage range: 2.7 V to 5.5 V 600 mA maximum load current 95% efficiency INPUT VOLTAGE OUTPUT VOLTAGE 2.7V TO 5.5V L 1.2V OR 1.375V Low duty cycle operation V LX IN C 1µH IN COUT Only 3 tiny external ceramic components 2.2µF 2.2µF ADP2102 3 MHz typical operating frequency Fixed output voltage of 1.2 V or 1.375 V FORCED CCM MODE FB/OUT Adjustable output voltage up to 3.3 V EN GND 0.01 µA shutdown supply current DCM/ Automatic power save mode CCM ON
001
Internal synchronous rectifier Internal soft start OFF
06631-
Internal compensation Enable/shutdown logic input Undervoltage lockout
Figure 1.
Current limit protection
The ADP2102 is available in both fixed and adjustable output
Thermal shutdown
voltage options with a 600 mA maximum output current. The fixed
Small 8-lead, 3 mm × 3 mm LFCSP
output voltage options are 1.2 V and 1.375 V. The adjustable output
APPLICATIONS
voltage options are available from 1.5 V to 3.3 V. The ADP2102 requires only three external components and consumes 0.01 µA
USB powered devices
in shutdown mode.
WLAN and gateways Point of loads
The ADP2102 is available in an 8-lead LFCSP and is specified
Processor core power from 5 V
for the −40°C to +85°C temperature range.
Digital cameras 100 VOUT = 1.375V PDAs and palmtop computers VIN = 2.7V TA = 25°C 95 Portable media players, GPS VIN = 3V 90 GENERAL DESCRIPTION %) 85
The ADP2102 is a synchronous step-down dc-to-dc converter
( VIN = 4.2V VIN = 3.6V
that converts a 2.7 V to 5.5 V unregulated input voltage to a lower
NCY E 80
regulated output voltage with up to 95% efficiency and 1%
ICI F F 75
accuracy. The low duty cycle capability of the ADP2102 is ideal for
E
USB applications or 5 V systems that power up submicron subvolt
70
processor cores. Its 3 MHz typical operating frequency and excel-
65
lent transient response allow the use of small, low cost 1 µH inductors and 2.2 µF ceramic capacitors. At medium-to-high
60 10 100 1000
052 load currents, it uses a current mode, pseudofixed frequency pulse-
LOAD CURRENT (mA)
06631- width modulation to extend battery life. To ensure the longest Figure 2. Efficiency vs. Load Current at VOUT = 1.375 V battery life in portable applications, the ADP2102 has a power save mode (PSM) that reduces the switching frequency under light load conditions to significantly reduce quiescent current.
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Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION TYPICAL APPLICATION CIRCUIT REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE BOUNDARY CONDITION ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION CONTROL SCHEME CONSTANT ON-TIME TIMER FORCED CONTINUOUS CONDUCTION MODE POWER SAVE MODE SYNCHRONOUS RECTIFICATION CURRENT LIMIT SOFT START ENABLE UNDERVOLTAGE LOCKOUT THERMAL SHUTDOWN APPLICATIONS INFORMATION INDUCTOR SELECTION INPUT CAPACITOR SELECTION OUTPUT CAPACITOR SELECTION TYPICAL APPLICATION CIRCUITS SETTING THE OUTPUT VOLTAGE EFFICIENCY CONSIDERATIONS Power Switch Conduction Losses Inductor Losses Switching Losses Transition Losses THERMAL CONSIDERATIONS DESIGN EXAMPLE Inductor Output Capacitor Input Capacitor Losses CIRCUIT BOARD LAYOUT RECOMMENDATIONS RECOMMENDED LAYOUT OUTLINE DIMENSIONS ORDERING GUIDE