AS1341 - Evaluation Board Application Note AS1341 Evaluation Board Application Note www.austriamicrosystems.com Revision 1.01 1-5 AS1341 - Evaluation Board Application Note General Description Board Description Figure 1: Board Description Connector Description Label Name Description A B C D E F VIN GND SHDNN OUT GND POK Input Voltage Ground Enable Jumper Power Output Connector Ground Power-OK Signal Info Input voltage ranging from 4.5V to 20V Jumper Description Label Name Description Info G ILIM: HIGH/LOW Current Limiter LOW ILIMIT: 0.7A HIGH ILIMIT: 1.4A H ON/OFF Enable Jumper ON OFF I 3.3V 5V Measurement Points Description Label Name Description J K L M LX GND VIN OUT External Conductor Power Supply Connectors for VBATT and Ground. Power Output Connector www.austriamicrosystems.com Info Revision 1.01 2-5 AS1341 - Evaluation Board Application Note Operational sequence This evaluation board comes with the AS1341. 1. If not present get the datasheet for the AS1341 from www.austriamicrosystems.com. Drive the IC on the Demoboard only with the recommended settings and values as described in the datasheet. 2. Connect a 4.5V to 20V power supply (VIN “A” and GND “B”). 3. Perform measurements at the measurement points “J” to “K”. If there are questions do not hesitate to contact us. See contact information at the end of the application note. Optional Features Setting the output voltage The AS1326 has a default output voltage of 3.3V. Additionally the output voltage can be set between 2.5 and 5V via an additionally resistor R1 which can be placed at “P”. The required resistor value for a certain output voltage can be calculated as shown in equation 1. R1=R2*(VOUT/VFB-1) (Eq1) R1=270kΩ*(VOUT/1.24V-1) (Eq2) Using the current limiter The ISET pin is used to adjust the inductor current limit and to implement the soft-start feature. With pin ISET connected to pin REF, the inductor current limit is set to 1.6A. With ISET connected to a resistor-divider network from pin REF to GND, the current limit is calculated as: ILIMIT=1.6A*RSS2/(RSS+RSS2) (Eq3) ILIMIT=1.6A*RSS2/(220kΩ+RSS2) (Eq4) Setting the soft-start On default the soft-start feature is disabled. The soft-start feature can be implemented by placing a resistor RSS (already soldered) between pin ISET and pin REF and a capacitor CSS between pin ISET and GND. At power-up, ISET is 0V and the LX current is tSS=RSS*CSS (Eq5) tSS=220kΩ*CSS (Eq6) If the current limiter resistance is also in use, the equation for the soft-start time would be: tSS=(RSS*RSS2/(RSS+RSS2))CSS (Eq7) tSS=(220kΩ*RSS2/(220kΩ+RSS2))CSS (Eq8) www.austriamicrosystems.com Revision 1.01 3-5 AS1341 - Evaluation Board Application Note Layout of evaluation board Board schematics and layout Figure 3: Schematics Figure 4: Top view Figure 5: Bottom view Assembly List Label CIN COUT or L1 RSS R1 RCC CRC RCC Info 33µF, ±10%, 10V, 150mΩ 100µF , ±10%, 10V, 50mΩ 82µF , ±20%, 6.3V, 18mΩ 3.3µH, 46mΩ, 1.8A 220kΩ 270kΩ 10Ω 330nF 10nF www.austriamicrosystems.com Type TPSC336K010R0150 T495D107M010ATE050 A700V826M006ATE018 MOS6020-332 Revision 1.01 Manufacturer AVX Kemet Kemet Coilcraft 4-5 AS1341 - Evaluation Board Application Note Copyright Copyright © 1997-2007, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, AustriaEurope. Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. All products and companies mentioned are trademarks or registered trademarks of their respective companies. Diclaimer Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. Austriamicrosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or lifesustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for each application. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard production flow, such as test flow or test location. The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However, austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems AG rendering of technical or other services. Contact Information Headquarters austriamicrosystems AG A-8141 Schloss Premstätten, Austria T. +43 (0) 3136 500 0 F. +43 (0) 3136 5692 For Sales Offices, Distributors and Representatives, please visit: http://www.austriamicrosystems.com/contact-us www.austriamicrosystems.com Revision 1.01 5-5