DN73 ZXSC300 Step down converter for 3W LED Description This design note shows the ZXSC300 or ZXSC310 driving a 3W LED. The input voltage ranges from 6.2V to 3.8V with a maximum output current of 1.11A at 6V input. A typical schematic diagram is shown in Figure 1. Figure 1 Ref. Value Schematic diagram Part number Manufacturer Comments U1 ZXSC300/310 Zetex LED Driver in SOT23-5 Q1 ZXMN2A01F Zetex SOT23 MOSFET D1 1A ZHCS1000 Zetex 1A Schottky in SOT23 L1 22H Generic Generic ISAT = 3A R1 20m⍀ Generic Generic 0805 size C1 100F Generic Generic C2 100F Generic Generic Table 1 Issue 2 - July 2006 © Zetex Semiconductors plc 2006 Bill of materials 1 www.zetex.com DN73 Typical operating characteristics (For typical application circuit where Tamb = 25°C unless otherwise stated) Figure 2 Performance graphs Europe Americas Asia Pacific Corporate Headquarters Zetex GmbH Streitfeldstraße 19 D-81673 München Germany Zetex Inc 700 Veterans Memorial Highway Hauppauge, NY 11788 USA Zetex (Asia Ltd) 3701-04 Metroplaza Tower 1 Hing Fong Road, Kwai Fong Hong Kong Zetex Semiconductors plc Zetex Technology Park, Chadderton Oldham, OL9 9LL United Kingdom Telefon: (49) 89 45 49 49 0 Fax: (49) 89 45 49 49 49 [email protected] Telephone: (1) 631 360 2222 Fax: (1) 631 360 8222 [email protected] Telephone: (852) 26100 611 Fax: (852) 24250 494 [email protected] Telephone: (44) 161 622 4444 Fax: (44) 161 622 4446 [email protected] For international sales offices visit www.zetex.com/offices Zetex products are distributed worldwide. For details, see www.zetex.com/salesnetwork This publication is issued to provide outline information only which (unless agreed by the company in writing) may not be used, applied or reproduced for any purpose or form part of any order or contact or be regarded as a representation relating to the products or services concerned. The company reserves the right to alter without notice the specification, design, price or conditions of supply of any product or service. www.zetex.com 2 Issue 2 - July 2006 © Zetex Semiconductors plc 2006