Dual 3 A, 20 V Synchronous Step-Down Regulator with Integrated High-Side MOSFET Data Sheet ADP2323 FEATURES TYPICAL APPLICATION CIRCUIT Input voltage: 4.5 V to 20 V R TOP1 1% output accuracy C C1 V IN R Integrated 90 m typical high-side MOSFET BOT1 C SS1 R C1 C IN1 Flexible output configuration Dual output: 3 A/3 A C BST1 Parallel single output: 6 A INTVCC L1 V OUT1 C INT MODE SW1 Programmable switching frequency: 250 kHz to 1.2 MHz SCFG External synchronization input with programmable phase TRK2 M1 C TRK1 OUT1 shift, or internal clock output DL1 VDRV Selectable PWM or PFM mode operation ADP2323 C DRV PGND GND Adjustable current limit for small inductor PGOOD2 External compensation and soft start DL2 PGOOD1 C OUT2 M2 Startup into precharged output SYNC Supported by ADIsimPower design tool RT SW2 V OUT2 R L2 OSC C APPLICATIONS BST2 Communications infrastructure R C2 V C IN SS2 Networking and servers R C BOT2 C2 C R IN2 TOP2 Industrial and instrumentation Healthcare and medical Figure 1. Intermediate power rail conversion DC-to-dc point of load applications inputs and power good outputs provide reliable power sequencing. GENERAL DESCRIPTION To enhance system reliability, the device also includes undervoltage The ADP2323 is a full featured, dual output, step-down dc-to- lockout (UVLO), overvoltage protection (OVP), overcurrent pro- dc regulator based on current-mode architecture. The ADP2323 tection (OCP), and thermal shutdown (TSD). integrates two high-side power MOSFETs and two low-side drivers The ADP2323 operates over the 40C to +125C junction for the external N-channel MOSFETs. The two pulse-width mod- ulation (PWM) channels can be configured to deliver dual 3 A temperature range and is available in a 32-lead LFCSP WQ outputs or a parallel-to-single 6 A output. The regulator operates package. from input voltages of 4.5 V to 20 V, and the output voltage can 100 be as low as 0.6 V. 95 The switching frequency can be programmed between 250 kHz 90 and 1.2 MHz, or synchronized to an external clock to minimize 85 interference in multirail applications. The dual PWM channels 80 run 180 out of phase, thereby reducing input current ripple as 75 well as reducing the size of the input capacitor. 70 The bidirectional synchronization pin can be programmed at 65 a 60, 90, or 120 phase shift, providing the possibility for a V = 5V 60 OUT stackable multiphase power solution. V = 3.3V OUT 55 The ADP2323 can be set to operate in pulse-frequency modulation 50 (PFM) mode at a light load for higher efficiency or in forced 0 0.5 1.0 1.5 2.0 2.5 3.0 PWM for noise sensitive applications. External compensation OUTPUT CURRENT (A) and soft start provide design flexibility. Independent enable Figure 2. Efficiency vs. Output Current at V = 12 V, f = 600 kHz IN SW Rev. 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EFFICIENCY (%) FB2 FB1 COMP2 COMP1 SS2 SS1 EN2 EN1 PVIN2 PVIN1 BST2 BST1 09357-002 09357-001ADP2323 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Overvoltage Protection .............................................................. 17 Applications ....................................................................................... 1 Undervoltage Lockout ............................................................... 18 Typical Application Circuit ............................................................. 1 Thermal Shutdown .................................................................... 18 General Description ......................................................................... 1 Applications Information .............................................................. 19 Revision History ............................................................................... 2 ADIsimPower Design Tool ....................................................... 19 Functional Block Diagram .............................................................. 3 Input Capacitor Selection .......................................................... 19 Specifications ..................................................................................... 4 Output Voltage Setting .............................................................. 19 Absolute Maximum Ratings ............................................................ 6 Voltage Conversion Limitations ............................................... 19 Thermal Resistance ...................................................................... 6 Current-Limit Setting ................................................................ 19 ESD Caution .................................................................................. 6 Inductor Selection ...................................................................... 20 Pin Configuration and Function Descriptions ............................. 7 Output Capacitor Selection....................................................... 20 Typical Performance Characteristics ............................................. 9 Low-Side Power Device Selection ............................................ 21 Theory of Operation ...................................................................... 15 Programming UVLO Input ...................................................... 21 Control Scheme .......................................................................... 15 Compensation Components Design ....................................... 21 PWM Mode ................................................................................. 15 Design Example .............................................................................. 23 PFM Mode ................................................................................... 15 Output Voltage Setting .............................................................. 23 Precision Enable/Shutdown ...................................................... 15 Current-Limit Setting ................................................................ 23 Separate Input Voltages ............................................................. 15 Frequency Setting ....................................................................... 23 Internal Regulator (INTVCC) .................................................. 15 Inductor Selection ...................................................................... 23 Bootstrap Circuitry .................................................................... 16 Output Capacitor Selection....................................................... 23 Low-Side Driver .......................................................................... 16 Low-Side MOSFET Selection ................................................... 24 Oscillator ..................................................................................... 16 Compensation Components ..................................................... 24 Synchronization .......................................................................... 16 Soft Start Time Programming .................................................. 24 Soft Start ...................................................................................... 16 Input Capacitor Selection .......................................................... 24 Peak Current-Limit and Short-Circuit Protection ................. 16 External Components Recommendation .................................... 25 Voltage Tracking ......................................................................... 17 Typical Application Circuits ......................................................... 26 Parallel Operation....................................................................... 17 Outline Dimensions ....................................................................... 31 Power Good ................................................................................. 17 Ordering Guide .......................................................................... 31 REVISION HISTORY 6/12Rev. 0 to Rev. A Change to Features Section ............................................................. 1 Added ADIsimPower Design Tool Section ................................. 19 7/11Revision 0: Initial Version Rev. A Page 2 of 32