October 2006 LM3404/04HV 1.0A Constant Current Buck Regulator for Driving High Power LEDs General Description Features The LM3404/04HV are monolithic switching regulators designed to deliver constant currents to high power LEDs. Ideal for automotive, industrial, and general lighting applications, they contain a high-side NFET switch with a minimum overtemperature current limit of 1.2A for step-down (Buck) regulators. Hysteretic control with controlled on-time coupled with an external resistor allow the converter output voltage to adjust as needed to deliver constant current to series and series-parallel connected LED arrays of varying number and type. Output current dimming via PWM, broken/open LED protection, low-power shutdown and thermal shutdown complete the feature set. Integrated 1.2A NFET VIN Range 6V to 42V (LM3404) VIN Range 6V to 75V (LM3404HV) 1.2A Output Current Over Temperature Cycle-by-Cycle Current Limit No Control Loop Compensation Required Separate PWM Dimming and Low Power Shutdown Supports all-ceramic output capacitors and capacitor-less outputs n Thermal shutdown protection n SO-8 Package n n n n n n n n Applications n n n n n LED Driver Constant Current Source Automotive Lighting General Illumination Industrial Lighting Typical Application 20205401 Connection Diagram 20205402 8-Lead Plastic SO-8 Package NS Package Number M08A © 2006 National Semiconductor Corporation DS202054 www.national.com LM3404/04HV 1.0A Constant Current Buck Regulator for Driving High Power LEDs ADVANCE INFORMATION LM3404/04HV 1.0A Constant Current Buck Regulator for Driving High Power LEDs Physical Dimensions inches (millimeters) unless otherwise noted SO-8 Package NS Package Number M08A National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. For the most current product information visit us at www.national.com. LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. BANNED SUBSTANCE COMPLIANCE National Semiconductor follows the provisions of the Product Stewardship Guide for Customers (CSP-9-111C2) and Banned Substances and Materials of Interest Specification (CSP-9-111S2) for regulatory environmental compliance. Details may be found at: www.national.com/quality/green. Lead free products are RoHS compliant. National Semiconductor Americas Customer Support Center Email: [email protected] Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530 85 86 Email: [email protected] Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 National Semiconductor Asia Pacific Customer Support Center Email: [email protected] National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: [email protected] Tel: 81-3-5639-7560