Using the EL7566 Demo Board ® Technical Brief July 9, 2003 TB415.1 Introduction The EL7566 is a high efficiency fullfeatured synchronous 6A step-down regulator. This document lists the completed schematic diagram and BOM, as well as the layout. With components on one side of the PCB, the complete converter occupies less than 0.72in2 of space. Please refer to the datasheet for the application of features. This demo board is preset to 1.8V for VO and operates at 500kHz switching frequency. The measured crossover frequencies are around 50kHz with the compensation values. Circuit Diagram U1 R0 C0 8200pF 7.68K C1 OPEN C2 1 CC SGND 28 2 VREF COSC 27 C7 270pF C11 OPEN C12 OPEN 0.022µF R2 R1 10.2K 12.7K VTJ C4 0.022µF TM R6 10K R5 L1 VOUT 10K SEL 2.7µH + C5 150µF GND 3 FB STN 26 STN 4 VO STP 25 STP 5 VTJ EN 24 EN 6 TM PG 23 7 SEL PG C8 VDD 22 1µF 8 LX VIN 21 9 LX VIN 20 10 LX VIN 19 11 LX PGND 18 12 LX PGND 17 13 LX PGND 16 14 NC NC 15 R4 OPEN R3 OPEN C9 1µF +C VIN 10 100µF GND LX EL7566CRE 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright © Intersil Americas Inc. 2003. All Rights Reserved. Elantec is a registered trademark of Elantec Semiconductor, Inc. All other trademarks mentioned are the property of their respective owners. Technical Brief 415 TABLE 1. DEMO BOARD BILL OF MATERIAL WITH SPCAP (VO = 1.8V) DESIGNATOR VALUE PACKAGE C0 8200pF 0603 Any X5R or X7R C2, C4 0.022µF 0603 Any X5R or X7R C5 (Note 1) 150µF/4V D-Size C7 270pF 5% 0603 Any C8 1µF 0603 Any X5R or X7R C9 1µF 0603 Any X5R or X7R C10 (Note 2) 100µF/6V D-Size R0 7.68K/1% 0603 Any R1 12.7K/1% 0603 Any R2 10.2K/1% 0603 Any R5 10K/1% 0603 Any R6 10K/1% 0603 Any L1 2.7µH U1 EL7566DRE HTSSOP-28 MANUFACTURER Panasonic PHONE # PART NUMBER 408-945-5660 EEFUD0G151(X)R Panasonic EEFUD0J101(X)R Coilcraft 847-639-6400 DO3316P-272HC Intersil 888-INTERSIL EL7566DRE NOTES: 1. May be substituted by Sanyo (619-661-6835) POSCAP 4TPE150M. 2. May be substituted by Sanyo POSCAP 6TPE100M or higher value. The output voltage can be as high as the input voltage minus the PMOS and inductor voltage drops. Use R1 and R2 to set the output voltage according to the following formula: R 1 V O = V FB × 1 + ------- R 2 Ceramic capacitors (X5R or X7R types only) can be use for the input and output with equivalent capacitance for C5 and C10. Different R0 and C0 are required. Table 3 lists the compensation values with MLCC capacitors. TABLE 3. FEEDBACK RESISTER AND COMPENSATION VALUES WITH MLCC CAPACITORS Where VFB=0.8V When the resisters are changed, please change the compensation capacitor C0 and resister R0. For the convenience, standard values of R1 and R2 are listed in Table 2. R5 and R6 can be eliminated if voltage margin feature is not used. Connect TM and SEL pins directly to ground. 1206, 1210, 1812, and D-size can be placed at C5 and C10 positions. TABLE 2. FEEDBACK RESISTER AND COMPENSATION VALUES (SPCAP) VO (V) C0 (pF) R0 (kΩ) R1 (kΩ) R2 (kΩ) 0.8 8200 3.57 0 Open 1 8200 4.42 2.49 10 1.2 8200 5.23 4.99 10 1.5 8200 6.49 10 11.5 1.8 8200 7.68 12.7 10.2 2.5 8200 10.5 21.5 10 3.3 8200 13.7 36 11.5 2 VO (V) C0 (µF) R0 (kΩ) R1 (kΩ) R2 (kΩ) 0.8 0.012 3.09 0 Open 1 0.012 3.57 2.49 10 1.2 0.012 4.42 4.99 10 1.5 0.012 5.23 10 11.5 1.8 0.012 6.49 12.7 10.2 2.5 0.012 7.68 21.5 10 3.3 0.012 10.5 36 11.5 Technical Brief 415 Demo Board Layout TOP SILKSCREEN TOP LAYER BOTTOM LAYER All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems. Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality Intersil products are sold by description only. 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 data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see www.intersil.com 3