Dual 5 A, 20 V Synchronous Step-Down Regulator with Integrated High-Side MOSFET Data Sheet ADP2325 FEATURES TYPICAL APPLICATION CIRCUIT Input voltage: 4.5 V to 20 V R V IN TOP1 1% output accuracy C C IN1 C1 Integrated 48 m typical high-side MOSFET C SS1 R BOT1 R Flexible output configuration C1 C BST1 Dual output: 5 A/5 A INTVCC C L1 V INT OUT1 MODE Parallel single output: 10 A SW1 SCFG Programmable switching frequency: 250 kHz to 1.2 MHz M1 C TRK2 OUT1 DL1 External synchronization input with programmable phase TRK1 VDRV shift or internal clock output C ADP2325 PGND DRV Selectable PWM or PFM mode operation GND M2 DL2 C OUT2 Adjustable current limit for small inductors PGOOD2 V L2 OUT2 PGOOD1 External compensation and soft start SW2 SYNC Startup into precharged output RT C BST2 R Supported by ADIsimPower design tool OSC R C2 R BOT2 APPLICATIONS V IN C C C C2 SS2 IN2 Communications infrastructure R TOP2 Networking and servers Industrial and instrumentation Figure 1. Healthcare and medical Intermediate power rail conversion GENERAL DESCRIPTION The ADP2325 is a full featured, dual output, step-down dc-to-dc Independent enable inputs and power-good outputs provide regulator based on a current mode architecture. The ADP2325 reliable power sequencing. To enhance system reliability, the device integrates two high-side power MOSFETs and two low-side drivers includes undervoltage lockout (UVLO), overvoltage protection for the external N-channel MOSFETs. The two pulse-width mod- (OVP), overcurrent protection, and thermal shutdown. ulation (PWM) channels can be configured to deliver dual 5 A The ADP2325 operates over the 40C to +125C junction outputs or a parallel-to-single 10 A output. The regulator operates temperature range and is available in a 32-lead LFCSP WQ from input voltages of 4.5 V to 20 V, and the output voltage can package. be as low as 0.6 V. 100 V = 5.0V OUT V = 3.3V OUT The switching frequency can be programmed from 250 kHz to 95 1.2 MHz, or it can be synchronized to an external clock to 90 minimize interference in multirail applications. The dual PWM 85 channels run 180 out of phase, thereby reducing input current 80 ripple as well as reducing the size of the input capacitor. 75 The bidirectional synchronization pin can be programmed at 70 a 60, 90, or 120 phase shift to provide for a stackable, multi- 65 phase power solution. 60 The ADP2325 can be configured to operate in pulse frequency 55 modulation (PFM) mode at a light load for higher efficiency or in forced PWM mode for noise sensitive applications. External 50 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 compensation and soft start provide design flexibility. OUTPUT CURRENT (A) Figure 2. Efficiency vs. Output Current at V = 12 V, f = 600 kHz IN SW Rev. A 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 www.analog.com license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. Fax: 781.461.3113 2012 Analog Devices, Inc. All rights reserved. EFFICIENCY (%) FB2 FB1 COMP2 COMP1 SS2 SS1 EN2 EN1 PVIN2 PVIN1 BST1 BST2 10036-002 10036-001ADP2325 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Overvoltage Protection .............................................................. 19 Applications ....................................................................................... 1 Undervoltage Lockout ............................................................... 19 Typical Application Circuit ............................................................. 1 Thermal Shutdown .................................................................... 19 General Description ......................................................................... 1 Applications Information .............................................................. 20 Revision History ............................................................................... 2 ADIsimPower Design Tool ....................................................... 20 Functional Block Diagram .............................................................. 3 Input Capacitor Selection .......................................................... 20 Specif icat ions ..................................................................................... 4 Output Voltage Setting .............................................................. 20 Absolute Maximum Ratings ....................................................... 6 Voltage Conversion Limitations ............................................... 20 Thermal Resistance ...................................................................... 6 Current-Limit Setting ................................................................ 20 ESD Caution .................................................................................. 6 Inductor Selection ...................................................................... 21 Pin Configuration and Function Descriptions ............................. 7 Output Capacitor Selection ....................................................... 21 Typical Performance Characteristics ............................................. 9 Low-Side Power Device Selection ............................................ 22 Theory of Operation ...................................................................... 16 Programming the UVLO Input ................................................ 22 Control Scheme .......................................................................... 16 Compensation Components Design ....................................... 23 PWM Mode ................................................................................. 16 Design Example .............................................................................. 24 PFM Mode ................................................................................... 16 Output Voltage Setting .............................................................. 24 Precision Enable/Shutdown ...................................................... 16 Current-Limit Setting ................................................................ 24 Separate Input Voltages ............................................................. 16 Frequency Setting ....................................................................... 24 Internal Regulator (INTVCC) .................................................. 16 Inductor Selection ...................................................................... 24 Bootstrap Circuitry .................................................................... 17 Output Capacitor Selection ....................................................... 24 Low-Side Driver .......................................................................... 17 Low-Side MOSFET Selection ................................................... 25 Oscillator ..................................................................................... 17 Compensation Components ..................................................... 25 Synchronization .......................................................................... 17 Soft Start Time Programming .................................................. 26 Soft Start ...................................................................................... 17 Input Capacitor Selection .......................................................... 26 Peak Current-Limit and Short-Circuit Protection ................. 17 External Components Recommendations .................................. 27 Voltage Tracking ......................................................................... 18 Typical Application Circuits ......................................................... 28 Parallel Operation....................................................................... 18 Packaging and Ordering Information ......................................... 32 Power Good ................................................................................. 19 Outline Dimensions ................................................................... 32 Ordering Guide .......................................................................... 32 REVISION HISTORY 7/12Rev. 0 to Rev. A Added ADIsimPower Design Tool Section ................................. 20 Changes to Ordering Guide .......................................................... 32 2/12Revision 0: Initial Version Rev. A Page 2 of 32