STEVAL-ISA047V2 1.5 A / 3.3 V step-down DC-DC converter demonstration board based on the ST1S03A Data brief Features ■ Step-down current mode PWM (1.5 MHz) DC-DC converter ■ 2% DC output voltage tolerance ■ Internal soft-start for start-up current limitation and power on delay of 50-100 µs ■ Typical efficiency: > 85% ■ Inhibit function ■ 1.5 A output current capability ■ Not switching quiescent current: max 1.5 mA (overtemperature range) ■ Switch VDS: max 200 mV @ ISW = 750 mA ■ Uses tiny capacitors and inductors ■ RoHS compliant STEVAL-ISA047V2 Description This demonstration board is based on the ST1S03A, an adjustable current mode PWM step-down DC-DC converter with internal 1.5 A power switch, packaged in a 6-lead DFN 3x3 mm. It's a complete 1.5 A switching regulator with its internal compensation eliminating additional component. The constant frequency, current mode, PWM architecture and stable operation with ceramic capacitors results in low, predictable output ripple. However, in order to maximize the power conversion efficiency with light load, the regulator reduces automatically the switching frequency when the output load becomes less than 250 mA typically. July 2009 Doc ID 15973 Rev 1 For further information contact your local STMicroelectronics sales office. 1/4 www.st.com 4 Circuit schematic 1 Circuit schematic Figure 1. 2/4 STEVAL-ISA047V2 Schematic diagram Doc ID 15973 Rev 1 STEVAL-ISA047V2 2 Revision history Revision history Table 1. Document revision history Date Revision 01-Jul-2009 1 Changes Initial release. Doc ID 15973 Rev 1 3/4 STEVAL-ISA047V2 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no liability whatsoever relating to the choice, selection or use of the ST products and services described herein. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. If any part of this document refers to any third party products or services it shall not be deemed a license grant by ST for the use of such third party products or services, or any intellectual property contained therein or considered as a warranty covering the use in any manner whatsoever of such third party products or services or any intellectual property contained therein. UNLESS OTHERWISE SET FORTH IN ST’S TERMS AND CONDITIONS OF SALE ST DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY WITH RESPECT TO THE USE AND/OR SALE OF ST PRODUCTS INCLUDING WITHOUT LIMITATION IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION), OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. UNLESS EXPRESSLY APPROVED IN WRITING BY AN AUTHORIZED ST REPRESENTATIVE, ST PRODUCTS ARE NOT RECOMMENDED, AUTHORIZED OR WARRANTED FOR USE IN MILITARY, AIR CRAFT, SPACE, LIFE SAVING, OR LIFE SUSTAINING APPLICATIONS, NOR IN PRODUCTS OR SYSTEMS WHERE FAILURE OR MALFUNCTION MAY RESULT IN PERSONAL INJURY, DEATH, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE. ST PRODUCTS WHICH ARE NOT SPECIFIED AS "AUTOMOTIVE GRADE" MAY ONLY BE USED IN AUTOMOTIVE APPLICATIONS AT USER’S OWN RISK. Resale of ST products with provisions different from the statements and/or technical features set forth in this document shall immediately void any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoever, any liability of ST. ST and the ST logo are trademarks or registered trademarks of ST in various countries. Information in this document supersedes and replaces all information previously supplied. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners. © 2009 STMicroelectronics - All rights reserved STMicroelectronics group of companies Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Philippines - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America www.st.com 4/4 Doc ID 15973 Rev 1