Using the EL7530 Evaluation Board ® Technical Brief February 22, 2005 TB449.0 Using the Evaluation Board 2. Chip Enable EL7530 is a highly efficiency 600mA synchronous step-down regulator in a tiny MSOP10 package. It operates at PFM mode at light load, automatically switches to PWM mode when the load increases to about 200mA. The no load quiescent current is only 120µA. The internal compensation makes it possible for the full-featured 600mA converter to occupy less than 0.18 in2 of PCB area with all components on one side. When EN pin is pulled to Ground, the regulator is disabled. It consumes less than 1µA of current. R5 can be removed and EN connected to VIN directly if this function is not needed, reducing the component count. 3. Sync Function When a sync signal is fed to the SYNC pin, the converter will operate at PWM mode only. The sync frequency can be 1.6MHz up to 12MHz. When this pin is tied HIGH, the converter operates at forced PWM mode all the time with switching frequency of 1.5MHz. When this pin is tied LOW, it operates at auto-switchable PFM/PWM mode. Therefore, R6 is not needed in actual application. 1. Output Adjustment Use R1 and R2 to adjust output voltage according to the following formula: R V O = 0.8 × 1 + ------2- R 1 4. Power Good Function When the output voltage reaches 90% of the set value, the PG goes to HIGH. Leave this pin open if the function is not used. Pull-up resister R4 can be removed. R1* C4 470pF 100kΩ R2 * 1 SGND FB 10 2 PGND VO 9 3 LX PG 8 PG 4 VIN EN 7 EN 124kΩ L1 VO 1.8µH VIN GND R3 100Ω C1 C2 10µF 10µF C3 0.1µF 5 VDD SYNC 6 U1 EL7530IY R4 * 100kΩ R5 * 100kΩ SYNC R6* 100kΩ * Optional depending on actual application. FIGURE 1. DEMO BOARD SCHEMATIC Evaluation Board Bill of Materials REFERENCE DESIGNATOR VALUE PACKAGE MANUFACTURER MANUFACTURER’S PART NUMBER MANUFACTURER’S PHONE NUMBER C1, C2 10µF/MLCC, X7R 1206 TDK C3216X7R1A106K 847-803-6100 C3 0.1µF/MLCC, X7R 0603 Any 1008PS-182M 847-639-6400 EL7530IY 888-INTERSIL L1 1.8µH R2 124K, 1% 0603 Any R1, R4, R5, R6 100K, 1% 0603 Any R3 100 0603 Any U1 EL7530IY MSOP10 Intersil C4 470pF 0603 ANY 1 Coilcraft CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-352-6832 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2005. All Rights Reserved All other trademarks mentioned are the property of their respective owners. Technical Brief 449 Demo Board Layout (Actual Size - 3” x 2”) FIGURE 2. SILKSCREEN TOP FIGURE 3. TOP LAYER FIGURE 4. BOTTOM LAYER 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 2 TB449.0 February 22, 2005