36 V,1 A, Synchronous, Step-Down DC-to-DC Regulator Data Sheet ADP2441 FEATURES TYPICAL CIRCUIT CONFIGURATION C3 Wide input voltage range of 4.5 V to 36 V Low minimum on time of 50 ns C C4 BST Maximum load current of 1 A V OUT High efficiency of up to 94% R Adjustable output down to 0.6 V TOP V IN FB VIN 1% output voltage accuracy R V BOTTOM OUT ADP2441 Adjustable switching frequency of 300 kHz to 1 MHz COMP SW Pulse skip mode at light load for power saving C C V IN OUT IN EN R PGND Precision enable input pin COMP Open-drain power good C COMP External soft start with tracking R FREQ Overcurrent-limit protection Shutdown current of less than 15 A Figure 1. UVLO and thermal shutdown 100 12-lead, 3 mm 3 mm LFCSP package V = 5V OUT V = 12V OUT Reference similar product ADP2442 with synchronization 90 capability 80 APPLICATIONS 70 V = 3.3V OUT 60 Point of load applications Distributed power systems 50 Industrial control supplies 40 Standard rail conversion to 24 V/12 V/5 V/3.3 V V = 24V IN 30 f = 300kHz SW GENERAL DESCRIPTION 20 The ADP2441 is a constant frequency, current mode control, 10 synchronous, step-down dc-to-dc regulator that is capable of 0 0.02 0.2 1 driving loads up to 1 A with excellent line and load regulation LOAD (A) characteristics. The ADP2441 operates with a wide input voltage Figure 2. Efficiency vs. Load Current, V = 24 V IN range of 4.5 V to 36 V, which makes it ideal for regulating power from a wide variety of sources. In addition, the ADP2441 has The ADP2441 uses hiccup mode to protect the IC from short very low minimum on time (50 ns) and is, therefore, suitable for circuits or from overcurrent conditions on the output. The external applications requiring a very high step-down ratio. programmable soft start limits inrush current during startup for a wide variety of load capacitances. Other key features include The output voltage can be adjusted from 0.6 V to 0.9 V VIN. tracking, input undervoltage lockout (UVLO), thermal shutdown High efficiency is obtained with integrated low resistance N- (TSD), and precision enable (EN), which can also be used as a channel MOSFETs for both high-side and low-side devices. logic level shutdown input. The switching frequency is adjustable from 300 kHz to 1 MHz with The ADP2441 is available in a 3 mm 3 mm, 12-lead LFCSP an external resistor. The ADP2441 also has an accurate power-good package and is rated for a junction temperature range of 40C (PGOOD) open-drain output signal. to +125C. At light load conditions, the regulator operates in pulse skip mode by skipping pulses and reducing switching losses to improve energy efficiency. In addition, at medium to heavy load conditions, the regulator operates in fixed frequency pulse-width modulation (PWM) mode to reduce electromagnetic interference (EMI). Rev. C Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20122015 Analog Devices, Inc. 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Technical Support www.analog.com EFFICIENCY (%) PGOOD AGND FREQ VCC SS/TRK BST 10581-002 10581-001ADP2441 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Applications Information .............................................................. 18 Applications ....................................................................................... 1 Selecting the Output Voltage .................................................... 18 General Description ......................................................................... 1 Setting the Switching Frequency .............................................. 18 Typical Circuit Configuration ......................................................... 1 Soft Start ...................................................................................... 19 Revision History ............................................................................... 2 External Components Selection ............................................... 19 Specifications ..................................................................................... 3 Boost Capacitor .......................................................................... 21 Absolute Maximum Ratings ............................................................ 5 VCC Capacitor............................................................................ 21 Thermal Resistance ...................................................................... 5 Loop Compensation .................................................................. 21 ESD Caution .................................................................................. 5 Large Signal Analysis of the Loop Compensation ................. 21 Pin Configuration and Function Descriptions ............................. 6 Design Example .............................................................................. 23 Typical Performance Characteristics ............................................. 7 Configuration and Components Selection ............................. 23 Internal Block Diagram ................................................................. 14 System Configuration ................................................................ 24 Theory of Operation ...................................................................... 15 Typical Application Circuits ......................................................... 25 Control Architecure ................................................................... 15 Design Example .......................................................................... 25 Adjustable Frequency ................................................................. 16 Other Typical Circuit Configurations ..................................... 26 Power Good ................................................................................. 16 Power Dissipation and Thermal Considerations ....................... 29 Soft Start ...................................................................................... 16 Power Dissipation....................................................................... 29 Tracking ....................................................................................... 16 Thermal Considerations ............................................................ 29 Undervoltage Lockout (UVLO) ............................................... 17 Evaluation Board Thermal Performance .................................... 30 Precision Enable/Shutdown ...................................................... 17 Circuit Board Layout Recommendations ................................... 31 Current-Limit and Short-Circuit Protection .......................... 17 Outline Dimensions ....................................................................... 32 Thermal Shutdown ..................................................................... 17 Ordering Guide .......................................................................... 32 REVISION HISTORY 8/15Rev. B to Rev. C Changes to Figure 45 ...................................................................... 14 6/14Rev. A to Rev. B Change to Features Section ............................................................. 1 11/12Rev. 0 to Rev. A Changes to Figure 1 .......................................................................... 1 Changed I Maximum Parameter from 2.2 mA to2 mA .......... 3 VIN Changes to Pin 3 and Pin 5 Descriptions ...................................... 6 Changes to Boost Capacitor Section ............................................ 21 Changes to Figure 66 ...................................................................... 31 Changes to Ordering Guide .......................................................... 32 6/12Revision 0: Initial Version Rev. C Page 2 of 32