Preliminary Technical Data ADP1828 Reference Design FCDC 00107 FEATURES A high density and cost-effective solution for low voltage DC-DC power conversion Input Voltage Range: 2.25 V – 2.75 V Output Voltage: 1 V Output Current: 12 A Ripple 20 mV ppk Transient step ±5%, 50% max load ADP1828 DESCRIPTION This ADP1828 reference design uses 2.25 V to 2.75 V for the input voltage, with a separate 3.3 V bias rail. The output voltage and current is: • VOUT1 = 1.0 V with a maximum output current of 12 A, Design criteria require no tracking or sequencing. The ripple and transient assumptions are 20 mV peak to peak voltage ripple and 5% deviation due to 50% instantaneous load step respectively. The nominal switching frequency is fixed at 300 kHz. Rev. 0 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. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2008 Analog Devices, Inc. All rights reserved. Preliminary Technical Data FCDC 00107 TABLE OF COTENTS Features....................................................................................................................................................................................................... 1 ADP1828 Description .............................................................................................................................................................................. 1 Revision History........................................................................................................................................................................................ 2 ADP1828 General Description ............................................................................................................................................................... 3 Schematic ................................................................................................................................................................................................... 3 Bill of Materials ......................................................................................................................................................................................... 4 Performance............................................................................................................................................................................................... 5 Notes: .......................................................................................................................................................................................................... 6 TABLE OF FIGURES Figure 1. Schematic ............................................................................................................................................................................. 3 Figure 2. Calculated Efficiency.......................................................................................................................................................... 5 Figure 3. Calculated Gain and Phase Response .............................................................................................................................. 5 REVISION HISTORY 3/12/2008—Revision 0: Initial Version Rev. 0 | Page 2 of 6 Preliminary Technical Data FCDC 00107 ADP1828 GENERAL DESCRIPTION The ADP1828 is a versatile and synchronous PWM voltage mode buck controller. It drives an all N-channel power stage to regulate an output voltage as low as 0.6 V to 85% of the input voltage and is sized to handle large MOSFETs for point-of-load regulators. The ADP1828 is ideal for a wide range of high power applications, such as DSP and processor core I/O power, and general-purpose power in telecommunications, medical imaging, PC, gaming, and industrial applications. It operates from input bias voltages of 3 V to 18 V with an internal LDO that generates a 5 V output for input bias voltages greater than 5.5 V. The ADP1828 operates at a pin-selectable, fixed switching frequency of either 300 kHz or 600 kHz, or at any frequency between 300 kHz and 600 kHz with a resistor. The switching frequency can also be synchronized to an external clock up to 2× the part’s nominal oscillator frequency. The clock output can be used for synchronizing additional ADP1828s (or the ADP1829 controllers), thus eliminating the need for an external clock source. The ADP1828 includes soft start protection to limit any inrush current from the input supply during startup, reverse current protection during soft start for a precharged output, as well as a unique adjustable lossless current-limit scheme utilizing external MOSFET RDSON sensing. For applications requiring power-supply sequencing, the ADP1828 provides a tracking input that allows the output voltage to track during startup, shutdown, and faults. The additional supervisory and control features include thermal overload, undervoltage lockout, and power good. The ADP1828 operates over the −40°C to +125°C junction temperature range and is available in a 20-lead QSOP. SCHEMATIC CKout 3.3Vbias Rcklo Rb0 Rckhi 2.5Vin Cin1 1 Rfhi Rflo FSync ENin 2.5Vin 2 Rsync 3 Ren1 Ren2 4 Rv5 Cvin Cv5 Rf1 Rc3 5 6 7 Cc1 Cc3 Rc1 Cc0 8 Freq Clkout Sync Clkset EN BST IN DH Vreg SW Gnd CSL Com Pgnd p FB DL TRK PV SS Pgd 19 18 9 Rt1 Rt2 Css Rt3 Rpg 10 Rbst QH1 17 Dbst Cbst 16 15 Ccl Rcl1 14 L1 Rcl2 13 Rf2 TRKin Gnd 20 12 QL1 Cdr 11 Gnd Rvcc Co1 Co2 PwrGd Vout 3.3Vbias Rpv Figure 1. Schematic Rev. 0 | Page 3 of 6 Preliminary Technical Data FCDC 00107 BILL OF MATERIALS Table 1. Bill of Materials Designator Part Number Manufacturer Value Package Comment U1 ADP1828 Analog Devices QH1 BSC020N03MS Infineon PG-TDSON-8 N-Channel MOSFET QH1, QL1 BSC016N03MS Infineon PG-TDSON-8 L1 PA1320.301NL Pulse 300nH 10.4mm x 8.0mm N-Channel MOSFET Power Inductor / DCR = .48mO / Ferrite / Bead Cin1 grm32er60j107m Murata 100uF 1210 Input MLCC / X5R / 6.3V Co1, Co2 grm32er60j107m Murata 100uF 1210 Output MLCC / X5R / 6.3V Cv5, Cpv C2012X7R1C105K TDK 1uF 0603 MLCC / X7R / 16V Rf1 Generic 1% Vishay 30.1k 0402 Feedback Resistor Rf2 Generic 1% Vishay 20.0k 0402 Feedback Resistor Rc3 Generic 10% Vishay 287ohms 0402 Compensation Resistor Cc3 Generic 10% Vishay 330pF 0402 Compensation Capacitor Rc1 Generic 10% Vishay 20.0k 0402 Compensation Resistor Cc1 Generic 10% Vishay 470pF 0402 Compensation Capacitor Cc0 Generic 10% Vishay 33pF 0402 Compensation Capacitor Css Generic 10% Vishay 10nF 0402 COG or X7R / Soft Start Capacitor Rpg Generic 10% Vishay 100k 0402 POK1 Resistor Rpv, Rb0 Generic 10% Vishay 10ohms 0402 Decoupling Resistor Rcl1 Generic 10% Vishay 1.40k 0402 Current Limit Resistor Ccl1 Generic 10% Vishay 33pF 0402 Current Limit Signal Filter Capacitor Dbst BAT54 Any Cbst Rt1, Rt2, Rvcc, Rcl2, Ren2, Rflow, Rckhi Rt3, Rbst, Ren1, Rsync, Rfhigh, Rcklo, Rv5 Generic 10% Vishay QSOP-20L SOD-323 100nF 0402 NP 0ohms Rev. 0 | Page 4 of 6 0402 Voltage Mode Controller Bootstrap Diode COG or X7R / Boost Capacitor Preliminary Technical Data FCDC 00107 PERFORMANCE Figure 2. Figure 3. Calculated Efficiency Calculated Gain and Phase Response Rev. 0 | Page 5 of 6 Preliminary Technical Data FCDC 00107 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. EB0561 Rev. 0 | Page 6 of 6