Using the EL7512 Demo Board ® Technical Brief April 12, 2002 TB421 3. IO - up to 310mA depending on input voltage, provided that diode and inductor can handle the corresponding currents (refer to data sheet for the chart) The complete schematic of EL7512 demo board is shown in Figure 1. With different components stuffed, this demo board can easily be configured into the applications shown in this application brief. The standard demo board being sent out is the complete 5V to 12V converter shown in Figure 2, which occupies less than 0.4 in2 area with components on top side only. Layout diagrams are given at the end of this document. 4. Switching frequency - can be set by R3 5. R4 can be 10Ω - 51Ω if VO is less than 10V. If VO is larger than 12V, it can be calculated by: V O – 10 R 4 = -------------------I DD where IDD is a function of switching frequency, as shown in the IDD vs FS curve. 1. VIN = 2V-5.5V. Can be higher with higher voltage rated C1 2. VO = 12V. Can be set according to the following formula: R V O = V FB × 1 + ------2- R 1 where VFB is shown in the VFB vs VDD curve. C21 VO4 D21 C22 C14 VO3 D12 C15 C11 VO2 D11 C12 C13 D1 L1 VO1 Q1 L2 VIN VO11 C1 R4 1 PGND LX 10 2 SGND VDD 9 C6 R2 3 RT FB 8 4 EN SS 7 5 LBI LBO 6 EN C8 C4 R3 R6 C5 C3 R1 R9 C7 R7 LBO R8 FIGURE 1. COMPLETE SCHEMATIC OF EL7512 DEMO BOARD 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. 2004. 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 421 L1 D1 VIN VO1 C1 R6 R4 1 PGND LX 10 2 SGND VDD 9 C5 C6 C4 R3 R2 3 RT FB 8 4 EN SS 7 5 LBI LBO 6 C3 R1 C10 FIGURE 2. 5V TO 12V CONVERTER EL7512 Bill of Materials for VO = 12V (Figure 2) FS = 670kHz REFERENCE DESIGNATOR VALUE MANUFACTURER R1 10kΩ/1%, 0603 Any R2 80.6kΩ/1%, 0603 Any R3 100kΩ, 0603 Any R4 1kΩ, 0603 Any R6 0Ω Any C1 10µF, 6.3V Panasonic C3 20nF, 0603 Any C4 0.1µF/16V, 0805 Any C5 47µF/20V, 1812 Vishay/Sprague C6 0.1µF/16V, 0805 Any C10 10nF, 0603 Any L1 10µH D1 MBR0520 EL7512 Bill of Materials for VO = 18V MANUFACTURER’S PHONE NUMBER MANUFACTURER’S PART NUMBER 408-945-5660 ECJ-3YB0J106K 207-324-4140 293D476X-020D20 Coilcraft 847-639-6400 DO1608C-103 On Semiconductor 800-282-9855 MBR0520 MANUFACTURER’S PHONE NUMBER MANUFACTURER’S PART NUMBER 408-945-5660 ECJ-3YB0J106K 408-945-5660 ECJ-4YF1E1062 (Figure 2) FS = 1.2MHz REFERENCE DESIGNATOR VALUE MANUFACTURER R1 10kΩ/1%, 0603 Any R2 121kΩ Any R3 47.5kΩ Any R4 2.26kΩ Any R6 0Ω Any C1 10µF, 6.3V Panasonic C3 20nF, 0603 Any C4 0.1µF/16V, 0805 Any C5 10µF/25V, 1812 Panasonic C6 0.1µF/16V, 0805 Any C10 10nF Any L1 6.8µH Coilcraft 847-639-6400 DO1608C-682 D1 MBR0520 On Semiconductor 800-282-9855 MBR0520 2 Technical Brief 421 EL7512 Bill of Materials For USB Applications (Figure 2) VIN = 4.25V - 5.25V, VO = 5V, FS = 670kHz REFERENCE DESIGNATOR VALUE MANUFACTURER MANUFACTURER’S PHONE NUMBER MANUFACTURER’S PART NUMBER R1 133kΩ/1%, 0603 Any R2 374kΩ/1%, 0603 Any R3 100kΩ, 0603 Any R4 51Ω, 0603 Any R6 0Ω Any C1 10µF, 6.3V Panasonic 408-945-5660 ECJ-3YB0J106K C3 20nF, 0603 Any C4 0.1µF Any C5 330µF Vishay/Sprague 207-324-4140 293D476X-020D20 Sanyo 408-749-9714 6TPB330M C6 0.1µF Any C10 10nF, 0603 Any L1 10µH Coilcraft 847-639-6400 DO1608C-103 D1 MBR0520 On Semiconductor 800-282-9855 MBR0520 3 Technical Brief 421 L1 VIN (2V-4V) D1 Q1 C1 R4 1 PGND LX 10 2 SGND VDD 9 C5 C6 R5 L2 VO11 (4V, 400mA) C4 R3 R2 3 RT FB 8 4 EN SS 7 5 LBI LBO 6 R6 C3 R1 C10 R7 R8 FIGURE 3. EL7512 WITH OUTPUT DISCONNECT Disconnect voltage at: R V IN = 0.22 × 1 + ------7- R 6 EL7512 Bill of Materials for VO = 4V (Figure 3) FS = 670kHz REFERENCE DESIGNATOR VALUE MANUFACTURER MANUFACTURER’S PHONE NUMBER MANUFACTURER’S PART NUMBER R1, R5, R8 10kΩ/1%, 0603 Any R2 20kΩ/1%, 0603 Any R3 100kΩ, 0603 Any R4 51Ω, 0603 Any R6 0Ω Any R7 56.2kΩ Any C1 10µF, 6.3V Panasonic 408-945-5660 ECJ-3YB0J106K C3 20nF, 0603 Any C4 0.1µF/16V, 0805 Any C5 330µF Vishay/Sprague 207-324-4140 293D476X-020D20 Sanyo 408-749-9714 6TPB330M 847-639-6400 DO1608C-103 800-282-9855 MBR0520 C6 0.1µF/16V, 0805 Any C10 10nF, 0603 Any L1 10µH Coilcraft L2 0Ω Any D1 MBR0520 On Semiconductor Q1 IRLML6402 IR 4 IRLML6402 Technical Brief 421 D11 D12 VO3 (14.5V) L1 VIN (2.7V- 4.2V) C11 D1 C14 C13 C1 R4 1 PGND LX 10 2 SGND VDD 9 C15 VO1 (5.1V) C5 C6 C4 R3 R2 3 RT FB 8 4 EN SS 7 5 LBI LBO 6 C3 R6 R1 C10 FIGURE 4. EL7512 WITH DUAL OUTPUTS EL7512 Bill of Materials (Figure 4) VO1 = 5.1V, VO3 = 14.5V, FS = 670kHz REFERENCE DESIGNATOR VALUE MANUFACTURER MANUFACTURER’S PHONE NUMBER MANUFACTURER’S PART NUMBER R1 133kΩ/1% Any R2 402kΩ/1% Any R3 100kΩ Any R4 51Ω Any R6 0Ω Any C1 10µF, 6.3V Panasonic 408-945-5660 ECJ-3YB0J106K C3 20nF Any C4, C6, C11, C14 0.1µF/16V Any C5 330µF Vishay/Sprague 207-324-4140 293D476X-020D20 C10 10nF, 0603 Any C13 1µF Any C15 4.7µF Panasonic 408-945-5660 ECJ-3YF1C4752 L1 10µH Coilcraft 847-639-6400 DO1608C-103 D1 MBR0520 On Semiconductor 800-282-9855 MBR0520 D2, D3 BAT54S Vishay/Telefunken 402-563-6866 BAT54S 5 Technical Brief 421 C21 VO4 (~9.5V) D21 C22 C11 VO2 (19.5V) D11 L1 C12 D1 VIN C1 VO1 (10V) R4 1 PGND LX 10 2 SGND VDD 9 C5 C6 C4 R3 R2 3 RT FB 8 4 EN SS 7 5 LBI LBO 6 R6 C3 R1 C10 FIGURE 5. EL7512 FOR TRIPLE OUTPUT EL7512 Triple Output Bill of Materials (Figure 5) VO1 = 10V, VO2 = 19.5V, VO4 = -9.5V REFERENCE DESIGNATOR VALUE MANUFACTURER MANUFACTURER’S PHONE NUMBER MANUFACTURER’S PART NUMBER R1 10kΩ/1%, 0603 Any R2 66.5kΩ/1%, 0603 Any R3 100kΩ, 0603 Any R4 51Ω, 0603 Any R6 0Ω Any C1 10µF, 6.3V Panasonic 408-945-5660 ECJ-3YB0J106K C3 20nF, 0603 Any C4, C6, C11, C21 0.1µF/16V, 0805 Any C5 47µF/20V, 1812 Vishay/Sprague 207-324-4140 293D476X-020D20 C10 10nF, 0603 Any C12, C22 4.7µF, 25V Panasonic 408-945-5660 ECJ-3YF1C4752 L1 10µH Coilcraft 847-639-6400 DO1608C-153 D1 MBR0520 On Semiconductor 800-282-9855 MBR0520 D11, D21 BAT54S Vishay/Telefunken 402-563-6866 BAT54S 6 Technical Brief 421 Typical Performance Curves 1.355 3.6 1.35 3.4 3.2 IDD (mA) VFB 1.345 1.34 1.335 1.33 3 2.8 2.6 2.4 1.325 1.32 VDD=10V VO=12V-18V 2.2 5 6 7 8 9 10 11 2 650 12 750 850 950 1050 1150 1250 FS (kHz) VDD FIGURE 6. VFB vs VDD FIGURE 7. IDD vs FS Demo Board Layout ® 2000 mil 2 in www.intersil.com 2000 mil 2 in FIGURE 8. TOP LAYER FIGURE 9. TOP SILKSCREEN 2000 mil 2000 mil FIGURE 10. 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 7