Wide Range Input, Dual/Two-Phase, DC-to-DC Synchronous Buck Controller Data Sheet ADP1850 FEATURES TYPICAL OPERATION CIRCUIT V Wide range input: 2.75 V to 20 V IN R RAMP1 Power stage input voltage: 1 V to 20 V Output voltage range: 0.6 V up to 90% V IN RAMP1 VIN Output current to more than 25 A per channel ADP1850 M1 Accurate current sharing between channels (interleaved) EN1 DH1 L1 EN2 BST1 Programmable frequency: 200 kHz to 1.5 MHz VDL V OUT1 SW1 R11 180 phase shift between channels for reduced input ILIM1 VCCO FB1 capacitance TRK1 M2 TRK2 0.85% reference voltage accuracy from 40C to +85C DL1 R12 R Integrated boost diodes CSG1 PGOOD1 PGOOD2 PGND1 Power saving mode (PSM) at light loads SYNC HI R RAMP2 FREQ Accurate power good with internal pull-up resistor LO RAMP2 V IN Accurate voltage tracking capability M3 L2 Independent channel precision enable DH2 COMP1 BST2 V Overvoltage and overcurrent limit protection COMP2 OUT2 SW2 R21 Externally programmable soft start, slope compensation and ILIM2 FB2 current sense gain M4 SS1 DL2 Synchronization input R22 SS2 R CSG2 Thermal overload protection AGND PGND2 Input undervoltage lockout (UVLO) Available in 32-lead 5 mm 5 mm LFCSP Figure 1. Single Phase Circuit APPLICATIONS The ADP1850 provides high speed, high peak current drive High current single and dual output intermediate bus and capability with dead-time optimization to enable energy point of load converters requiring sequencing and efficient power conversion. For low load operation, the device tracking capability, including converters for: can be configured to operate in power saving mode (PSM) by Point-of-load power supplies skipping pulses and reducing switching losses to improve the Telecom base station and networking energy efficiency at light load and standby conditions. Consumer The accurate current limit (6%) allows the power architect to Industrial and instrumentation design within a narrower range of tolerances and can reduce Healthcare and medical overall converter size and cost. GENERAL DESCRIPTION The ADP1850 provides a configurable architecture capable The ADP1850 is a configurable dual output or two-phase, single of wide range input operation to provide the designer with output dc-to-dc synchronous buck controller capable of running maximum re-use opportunities and improved time to market. from commonly used 3.3 V to 12 V (up to 20 V) voltage inputs. Additional flexibility is provided by external programmability The device operates in current mode for improved transient of loop compensation, soft start, frequency setting, power response and uses valley current sensing for enhanced noise saving mode, current limit and current sense gain can all be immunity. programmed using external components. The architecture enables accurate current sharing between The ADP1850 includes a high level of integration in a small size interleaved phases for high current outputs. package. The start-up linear regulator and the boot-strap diode for the high side drive are included. Protection features include: The ADP1850 is ideal in system applications requiring multiple undervoltage lock-out, overvoltage, overcurrent/short-circuit output voltages: the ADP1850 includes a synchronization fea- and over temperature. The ADP1850 is available in a compact ture to eliminate beat frequencies between switching devices 32-lead LFCSP 5 mm 5 mm thermally enhanced package. provides accurate tracking capability between supplies and includes precision enable for simple, robust sequencing. 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. 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Technical Support www.analog.com 09440-001ADP1850 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Accurate Current-Limit Sensing .............................................. 17 Applications ....................................................................................... 1 Setting the Slope Compensation .............................................. 17 General Description ......................................................................... 1 Setting the Current Sense Gain ................................................ 17 Typical Operation Circuit ................................................................ 1 Input Capacitor Selection .......................................................... 18 Revision History ............................................................................... 2 Input Filter ................................................................................... 18 Specifications ..................................................................................... 3 Boost Capacitor Selection ......................................................... 18 Absolute Maximum Ratings ............................................................ 5 Inductor Selection ...................................................................... 18 ESD Caution .................................................................................. 5 Output Capacitor Selection....................................................... 19 Simplified Block Diagram ............................................................... 6 MOSFET Selection ..................................................................... 19 Pin Configuration and Function Descriptions ............................. 7 Loop Compensation (Single Phase Operation) ..................... 21 Typical Performance Characteristics ............................................. 9 Configuration and Loop Compensation (Dual-Phase Operation) ................................................................................... 22 Theory of Operation ...................................................................... 12 Switching Noise and Overshoot Reduction ............................ 22 Control Architecture .................................................................. 12 Voltage Tracking ......................................................................... 23 Oscillator Frequency .................................................................. 12 Indepdendent Power Stage Input Voltage ............................... 24 Modes of Operation ................................................................... 13 PCB Layout Guidelines .................................................................. 25 Synchronization .......................................................................... 13 MOSFETs, Input Bulk Capacitor, and Bypass Capacitor ...... 25 Synchronous Rectifier and Dead Time ................................... 14 High Current and Current Sense Paths ................................... 25 Input Undervoltage Lockout ..................................................... 14 Signal Paths ................................................................................. 25 Internal Linear Regulator .......................................................... 14 PGND Plane ................................................................................ 25 Overvoltage Protection .............................................................. 14 Feedback and Current-Limit Sense Paths ............................... 25 Power Good ................................................................................. 14 Switch Node ................................................................................ 26 Short-Circuit and Current-Limit Protection .......................... 15 Gate Driver Paths ....................................................................... 26 Shutdown Control ...................................................................... 15 Output Capacitors ...................................................................... 26 Thermal Overload Protection ................................................... 15 Typical Operating Circuits ............................................................ 27 Applications Information .............................................................. 16 Outline Dimensions ....................................................................... 31 Setting the Output Voltage ........................................................ 16 Ordering Guide .......................................................................... 31 Soft Start ...................................................................................... 16 Setting the Current Limit .......................................................... 16 REVISION HISTORY 5/2017Rev. B to Rev. C 4/2012Rev. 0 to Rev. A Changes to Oscillator Frequency Section.................................... 12 Changes to Setting the Current Sense Gain Section .................. 17 Updated Outline Dimensions ....................................................... 31 2/2017Rev. A to Rev. B 11/2010Revision 0: Initial Version Changed CP-32-11 to CP-32-12 .................................. Throughout Changes to Oscillator Frequency Section.................................... 12 Updated Outline Dimensions ....................................................... 31 Changes to Ordering Guide .......................................................... 31 Rev. C Page 2 of 32