20 V, 6 A Synchronous Step-Down Regulator with Low-Side Driver Data Sheet ADP2381 FEATURES TYPICAL APPLICATIONS CIRCUIT V Input voltage: 4.5 V to 20 V IN 1 16 PVIN BST Integrated 44 m high-side MOSFET L C V BST OUT 2 15 C IN PVIN SW 0.6 V 1% reference voltage over temperature 3 14 C OUT UVLO SW Continuous output current: 6 A ADP2381 FET 4 13 PGOOD LD Programmable switching frequency: 250 kHz to 1.4 MHz 12 5 C RT VREG VREG Synchronizes to external clock: 250 kHz to 1.4 MHz R OSC 6 11 SYNC PGND 180 out-of-phase synchronization 7 10 EN/SS GND R TOP Programmable UVLO C 8 9 SS Power-good output COMP FB R External compensation BOT C C EA R C EA Internal soft start with external adjustable option Startup into a precharged output Supported by ADIsimPower design tool C CP EA Figure 1. APPLICATIONS 100 Communication infrastructure 95 Networking and servers 90 Industrial and instrumentation Healthcare and medical 85 Intermediate power rail conversion 80 DC-to-dc point of load application 75 70 65 60 V = 3.3V OUT V = 5V OUT 55 V = 1.2V OUT 50 0 1 2 3 4 5 6 OUTPUT CURRENT (A) Figure 2. ADP2381 Efficiency vs. Output Current, V = 12 V, f = 250 kHz IN SW GENERAL DESCRIPTION The ADP2381 is a current mode control, synchronous, step- External compensation and an adjustable soft start provide down, dc-to-dc regulator. It integrates a 44 m power MOSFET design flexibility. The power-good output provides simple and reliable power sequencing. Additional features include and a low-side driver to provide a high efficiency solution. The ADP2381 runs from an input voltage of 4.5 V to 20 V and can programmable undervoltage lockout (UVLO), overvoltage deliver 6 A of output current. The output voltage can be protection (OVP), overcurrent protection (OCP), and thermal adjusted to 0.6 V to 90% of the input voltage. The switching shutdown (TSD). frequency of the ADP2381 can be programmed from The ADP2381 operates over the 40C to +125C junction 250 kHz to 1.4 MHz or fixed at 290 kHz or 550 kHz. The temperature range and is available in a 16-lead TSSOP EP synchronization function allows the switching frequency to be package. synchronized to an external clock to minimize system noise. Rev. 0 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. 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EFFICIENCY (%) 10209-002 10209-001ADP2381 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Applications Information .............................................................. 15 Applications ....................................................................................... 1 Input Capacitor Selection .......................................................... 15 Typical Applications Circuit ............................................................ 1 Output Voltage Setting .............................................................. 15 General Description ......................................................................... 1 Voltage Conversion Limitations ............................................... 15 Revision History ............................................................................... 2 Inductor Selection ...................................................................... 15 Specifications ..................................................................................... 3 Output Capacitor Selection....................................................... 17 Absolute Maximum Ratings ............................................................ 5 Low-Side Power Device Selection ............................................ 17 Thermal Information ................................................................... 5 Programming Input Voltage UVLO ........................................ 18 ESD Caution .................................................................................. 5 Compensation Design ............................................................... 18 Pin Configuration and Function Description .............................. 6 ADIsimPower Design Tool ....................................................... 19 Typical Performance Characteristics ............................................. 7 Design Example .............................................................................. 20 Functional Block Diagram ............................................................ 12 Output Voltage Setting .............................................................. 20 Theory of Operation ...................................................................... 13 Frequency Setting ....................................................................... 20 Control Scheme .......................................................................... 13 Inductor Selection ...................................................................... 20 Internal Regulator (VREG) ....................................................... 13 Output Capacitor Selection....................................................... 20 Bootstrap Circuitry .................................................................... 13 Low-Side MOSFET Selection ................................................... 21 Low-Side Driver .......................................................................... 13 Compensation Components ..................................................... 21 Oscillator ..................................................................................... 13 Soft Start Time Program ........................................................... 21 Synchronization .......................................................................... 13 Input Capacitor Selection .......................................................... 21 Enable and Soft Start .................................................................. 13 Schematic for Design Example ................................................. 21 Power Good ................................................................................. 14 External Components Recommendation .................................... 23 Peak Current Limit and Short-Circuit Protection ................. 14 Circuit Board Layout Recommendations ................................... 25 Overvoltage Protection (OVP) ................................................. 14 Typical Application Circuits ......................................................... 27 Undervoltage Lockout (UVLO) ................................................ 14 Outline Dimensions ....................................................................... 28 Thermal Shutdown ..................................................................... 14 Ordering Guide .......................................................................... 28 REVISION HISTORY 3/12Revision 0: Initial Version Rev. 0 Page 2 of 28