STEVAL-ISA108V1 4 A, 850 kHz fixed-frequency PWM synchronous step-down demostration board based on the ST1S41 in a VFQFPN package Data brief Features 4 to 18 V input voltage Output voltage adjustable from 0.8 V 850 kHz switching frequency Internal soft-start Integrated 95 m and 69 m power MOSFETs All ceramic capacitor Enable function Cycle-by-cycle current limiting Current fold-back short-circuit protection RoHS compliant Description Based on the ST1S41 step-down switching regulator, the STEVAL-ISA108V1 demonstration board is an internally-compensated 850 kHz fixed-frequency PWM synchronous step-down converter. The ST1S41 operates from 4.0 V to 18 V input, while it regulates an output voltage as low as 0.8 V and up to VIN (100% duty cycle). The ST1S41 integrates a 95 m high side switch and 69 m low side synchronous rectifier, resulting in very high efficiency with very low output voltages. The peak current mode control with internal compensation offers a compact solution with a minimum component count. February 2013 Doc ID 024148 Rev 1 For further information contact your local STMicroelectronics sales office. 1/4 www.st.com 4 Schematic diagram STEVAL-ISA108V1 1 Schematic diagram Figure 1. STEVAL-ISA108V1 circuit schematic 2/4 Doc ID 024148 Rev 1 STEVAL-ISA108V1 2 Revision history Revision history Table 1. Document revision history Date Revision 12-Feb-2013 1 Changes Initial release. Doc ID 024148 Rev 1 3/4 STEVAL-ISA108V1 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 TWO AUTHORIZED ST REPRESENTATIVES, 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. (c) 2013 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 024148 Rev 1