Preliminary Technical Data ADP1821 Reference Design FCDC 00100 FEATURES One Output Voltage: 5 V Output Current: 4 A Input voltage: 12.0-44.0 V Ripple 2% ppk of Output Voltage Transient step ±5%, 50% max load ADP1821 REFERENCE DESIGN DESCRIPTION This ADP1821 Reference Design uses 12.0 V to 44.0 V for the input voltage. The output voltage and current is as follows: • VOUT1 = 5.0 V with a maximum output current of 4 A, The ripple and transient assumptions are 2% peak to peak voltage ripple and 5% deviation due to 50% instantaneous load step. The switching frequency is fixed at 300 kHz for VOUT1. Maximum non-operating input voltage of 55 V can be sustained indefinitely. Designed for nominal efficiency of 92% at 24 V in. Rev. 1 Reference designs are as supplied “as is” and without warranties of any kind, express, implied, or statutory including, but not limited to, any implied warranty of merchantability or fitness for a particular purpose. No license is granted by implication or otherwise under any patents or other intellectual property by application or use of reference designs. 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 rights of third parties that may result from its use. Analog Devices reserves the right to change devices or specifications at any time without notice. Trademarks and registered trademarks are the property of their respective owners. Reference designs are not authorized to be used in life support devices or systems. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. www.analog Tel: 781.329.4700 Fax: 781.461.3113 ©2008 Analog Devices, Inc. All rights rese Preliminary Technical Data FCDC 00100 TABLE OF CONTENTS Features....................................................................................................................................................................................................... 1 ADP1821 Reference Design Description .............................................................................................................................................. 1 Revision History........................................................................................................................................................................................ 2 General Description ................................................................................................................................................................................. 3 ADP1821................................................................................................................................................................................................ 3 Schematic ................................................................................................................................................................................................... 4 Bill of Materials ......................................................................................................................................................................................... 5 TABLE OF FIGURES Figure 1. Schematic 5.0 V @ 4 A ....................................................................................................................................................... 4 REVISION HISTORY 2/8/2008—Revision 1: Initial Version Rev. 1 | Page 2 of 6 Preliminary Technical Data FCDC 00100 GENERAL DESCRIPTION ADP1821 The ADP1821 is a versatile and inexpensive, synchronous, pulse width-modulated (PWM), voltage-mode, step-down controller. It drives an all N-channel power stage to regulate an output voltage as low as 0.6 V. The ADP1821 can be configured to provide output voltages from 0.6 V to 85% of the input voltage and is sized to handle large MOSFETs for point-of-load regulators. The ADP1821 is well suited for a wide range of high power applications, such as DSP and processor core power in telecom, medical imaging, high performance servers, and industrial applications. It operates from a 3.0 V to 5.5 V supply with a power input voltage ranging from 1.0 V to 24 V. The ADP1821 operates at a pin-selectable, fixed switching frequency of either 300 kHz or 600 kHz, minimizing external component size and cost. For noise-sensitive applications, it can be synchronized to an external clock to achieve switching frequencies between 300 kHz and 1.2 MHz. The ADP1821 includes soft start protection to limit the inrush current from the input supply during startup, reverse current protection during soft start for precharged outputs, as well as a unique adjustable lossless current-limit scheme utilizing external MOSFET sensing. The ADP1821 operates over the –40°C to +85°C temperature range and is available in a 16-lead QSOP. Rev. 1 | Page 3 of 6 Preliminary Technical Data FCDC 00100 SCHEMATIC Figure 1. Schematic 5.0 V @ 4 A 5.0V at 4A Vin Rz Rzc Dvcc L1 Vo5V0 Rcl Ccl Co2 Co1 Qpv Db Cin1 Dcl3 Rbst Dcl1 Dcl2 QH1 QL1 Rpv BST Cz PVCC Cb DH Csn Rin Cpv DL U1 SW Rsn PGND Rlim Rsw SYNC CSL Clim ADP1821ARQZ Reh FREQ VCC SHDN COMP PWGD FB GND SS Cvcc Rel Cc1 Rpg Css Cc2 Rc1 Cc0 Rc2 Rf2 Rf1 Rev. 1 | Page 4 of 6 Preliminary Technical Data FCDC 00100 BILL OF MATERIALS Table 1. Vout1 Bill of Materials (5.0 V) Description Designator Quantity Manufacturer MFR# Capacitor Ceramic COG 820p 0603 50V Cc0 1 Vishay Generic Capacitor Ceramic X7R 47n 0603 16V Cc1 1 Vishay Generic Capacitor Ceramic X7R 4.7n 0603 50V Cc2 Cvcc, Cb, Css, Cpv, Cz, Ccl 1 Vishay Generic 6 Vishay Generic Capacitor Ceramic COG 33p 0603 50V Clim 1 Vishay Generic Capacitor Ceramic X7R 1n 0603 50V Csn 1 Vishay Generic Capacitor Ceramic X7R 1u 1206 100V Cin1 1 Murata GRM31CR72A105KA01L Capacitor Ceramic X7R 100n 0603 25V Capacitor Ceramic X7R 22u 1210 16V Co1 1 TDK C3225X7R1C226M Capacitor Polymer 330u D-case SMT 6.3V Co2 1 Kemet T525D337M006ATE025 Diode Zener 200mW SOD-323 28V Dcl2 1 Diodes inc MMSZ5255BS Diode Zener 200mW SOD-323 4.7V Dvcc 1 Diodes inc MMSZ5230BS Diode Schottky 200mA SOD-323 30V Db, Dcl3 2 Diodes inc BAT54WS Diode Fast Recovery 1A PowerDI-123 200V Db 1 Diodes inc DFLU1200 Transformer Ferrite 50uH 20mmx30mm L1 1 Coilcraft FA2898-ALD MMBTA05 Single NPN SOT-23 60V Qpv 1 Diodes inc Single N-Channel MOSFET D-pak 100V QH1 1 IR IRLR3110 Single N-Channel MOSFET TDSON-8 30V QL1 1 Infineon BSC025N03LS Thick Film 0 Ohm jumper 0603 Rsw 1 Vishay Generic 5% Thick Film 10 Ohms 0603 Rin, Rpv, Rbst 3 Vishay Generic 1% Thick Film 20.0k 0603 Rf1, Rel 2 Vishay Generic 1% Thick Film 2.74k 0603 Rf2 1 Vishay Generic 1% Thick Film 2.00k 0603 Rc2 1 Vishay Generic 1% Thick Film 866 Ohms 0603 Rlim 1 Vishay Generic 1% Thick Film 3.01k 0603 Rc1 1 Vishay Generic 1% Thick Film 10.0k 0603 Rpg 1 Vishay Generic 5% Thick Film 10 Ohms 0805 Rsn 1 Vishay Generic 1% Thick Film 4.99k 0805 Rzc 1 Vishay Generic 1% Thick Film 49.9k 0805 Rz 1 Vishay Generic 1% Thick Film 107k 0805 Reh 1 Vishay Generic 1% Thick Film 2.00k 1206 Rcl 1 Generic 1 chan 300k to 600k PWM QSOP-16 U1 1 Vishay Analog Devices Rev. 1 | Page 5 of 6 ADP1821ARQZ Preliminary Technical Data FCDC 00100 NOTES If a different number, or different type of output capacitors are used on the switching outputs the loop compensation components may need adjustment. ©2008 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. EB Rev. 1 | Page 6 of 6