Application Note 1600 Author: Huong Doan Dual 800mA Low Quiescent Current High Efficiency Synchronous Buck Regulator-Small Form Factor Description Key Features The ISL8088EVAL2Z kit is intended for use by individuals with requirements for Point-of-Load applications sourcing from 2.75V to 5.5V. The ISL8088EVAL2Z board is used to demonstrate the performance of the ISL8088 low quiescent current mode converter. • Dual 800mA High Efficiency Synchronous Buck Regulator with up to 97% Efficiency The ISL8088 is offered in a 3mmx3mm 10 Ld DFN package with 1mm maximum height. The complete converter occupies less than 0.120in2 area. • 800mA Guaranteed Output Current per channel • Power-Goods (PG) output with 1ms Delay • 2.75V to 5.5V Supply Voltage • 3% Output Accuracy Over-Temperature/Load/Line • Start up with Pre-biased Output • Internal Digital Soft-Start - 2ms Recommended Equipment • Soft-Stop Output Discharge During Disabled The following materials are recommended to perform testing: • 30µA Quiescent Supply Current in PFM Mode • 0V to 10V Power Supply with at least 3A source current capability or 5V battery • Selectable Forced PWM Mode and PFM Mode • External Synchronization up to 4MHz • Electronic Loads capable of sinking current up to 3A • Typical 6.5µA Logic Controlled Shutdown Current • Digital Multimeters (DMMs) • 100% Maximum Duty Cycle for Lowest Dropout • 100MHz quad-trace oscilloscope • Internal Current Mode Compensation • Signal generator • Peak Current Limiting. Quick Setup Guide • Over-Temperature Protection 1. Ensure that the circuit is correctly connected to the supply and loads prior to applying any power. • Independent Enable 2. Connect the bias supply to VIN. Plus terminal to VIN and negative return to P1. 3. Turn on the power supply. 4. Verify the output voltage is 2.5V for VOUT1 and 1.8V for VOUT2. VIN PFM VIN R1 100k SYNC U1 R9 OPEN PWM L1 1 1 2 3 4 5 11 2 2.2µH A C1 10µF VOUT1 C5 OPEN C8 10µF C2 10µF C3 10PF ISL8088IRZ R2 316k P1 10 9 8 7 6 A L2 1 2 2.2µH VOUT2 VOUT2 R5 200k C5 C4 10PF 10µF C7 OPEN A A P2 PGND1 FB1 FB2 EN1 EN2 VIN PG LX1 LX2 NC SYNCH EP A R6 100k R3 100k A A Note: Please keep FB1, FB2 pins traces short FIGURE 1. ISL8088EVAL2Z SCHEMATIC May 20, 2013 AN1600.1 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2010, 2013. All Rights Reserved Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries. All other trademarks mentioned are the property of their respective owners. 2 FIGURE 3. BOTTOM SILK SCREEN TABLE 1. BILL OF MATERIALS PART NUMBER QTY UNIT ISL8088EVAL2ZREVAPCB 1 ea GRM21BR60J106KE01-T 4 ea H1046-DNP 0 REFERENCE DESIGNATOR DESCRIPTION MANUFACTURER PART MANUFACTURER AN1600.1 May 20, 2013 PWB-PCB, ISL8088EVAL2Z, REVA, ROHS IMAGINEERING INC ISL8088EVAL2ZREVAPCB C1, C2, C4, C8 CAPACITOR, SMD, 0805, 10µF, 6.3V, 10%, X5R MURATA GRM21BR60J106KE01L ea C6, C7 CAP,SMD, 0805, DNP-PLACE HOLDER, ROHS 500R07S100JV4T-T 2 ea C3, C5 CAP-RF HIQ, SMD, 0402, 10pF, 50V, 5%, COG, ROHS JOHANSON TECHNOLOGY 500R07S100JV4T MDT2520-CR2R2M 2 ea L1, L2 COIL-PWR INDUCTOR, SMD, 2520, 2.2µH, 20%, 1.35A, ROHS TOKO MDT2520-CR2R2M 5000 3 ea VIN, VOUT1, VOUT2 CONN-MINI TEST PT, VERTICAL, RED, ROHS KEYSTONE 5000 5001 2 ea P1, P2 CONN-MINI TEST PT, VERTICAL, BLK, ROHS KEYSTONE 5001 ISL8088IRZ 1 ea U1 IC-DUAL SYNC. BUCK REGULATOR, 10P, DFN, 3X3, ROHS INTERSIL ISL8088IRZ H2510-01003-1/16W1-T 3 ea R1, R3, R6 RES, SMD, 0402, 100k, 1/16W, 1%, TF, ROHS PANASONIC ERJ2RKF1003 H2510-02003-1/16W1-T 1 ea R5 RES, SMD,0402, 200k, 1/16W, 1%, TF, ROHS ROHM MCR01MZPF2003 H2510-03163-1/16W1-T 1 ea R2 RES, SMD, 0402, 316k, 1/16W, 1%, TF, ROHS PANASONIC ERJ-2RKF3163X H2510-DNP 0 ea R9 RES, SMD, 0402, DNP, DNP, DNP, TF, ROHS Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that the Application Note or Technical Brief is current before proceeding. For information regarding Intersil Corporation and its products, see www.intersil.com Application Note 1600 FIGURE 2. TOP COMPONENTS