AS1331 - Demo Board Manual Buck-Boost Converter Demo Board Manual AS1331 300mA Buck-Boost Synchronous DC/DC Converter www.austriamicrosystems.com/DC-DC_Buck-Boost/AS1331 www.austriamicrosystems.com Revision 1.01 1-5 AS1331 - Demo Board Manual Buck-Boost Converter General Description Board Description Figure 1: Board Description - Connectors Figure 2: Board Description – Measurement Points Connector Description Label Name Description Info A B VIN GND Supply Voltage Ground Supply voltage ranging from 1.8V to 5.5V C EN Enable Connector D VOUT Output Voltage Logic “high”: normal operation Logic “low”: shutdown; quiescent current <1µA If an external signal is applied remove jumper “N”. Output voltage ranging from 2.5V to 3.3V Measurement Point Description Label Name Description E F G H I J K L M VIN SW1 SW2 VOUT EN FB GND LBO LBI Supply Voltage Info External Inductor Output Voltage Enable Voltage Feedback Voltage Ground Low Battery Output Low Battery Input Measurement Points ON: The AS1331 is on. N EN OFF; The AS1324 is off and the current into Vin is <1µA (typ). Enable No Jumper: Connect a valid enable signal via external connector “C”. EXT: Pin LBI is connected to the voltage divider R4/R5. LBO depends on voltage divider. O LBI Low Battery Input GND / EXT GND: Pin LBI is connected to GND. LBO is referenced to VOUT via internal voltage divider. No Jumper: not allowed! LBI must have a valid signal www.austriamicrosystems.com Revision 1.01 2-5 AS1331 - Demo Board Manual Buck-Boost Converter VOUT: LBI voltage divider is referenced to VOUT. P LBI Low Battery Input VIN / OUT VIN: LBI voltage divider is referenced to VIN. No Jumper: LBI voltage divider has no signal. VOUT: Signal on LBO is connected via R3 to VOUT. Q LBO VIN: Signal on LBO is connected via R3 to VIN. Low Battery Output No Jumper: An external pull-up resistor is required for a valid LBO signal. Getting Started The AS1331 Demoboard is designed to work with the AS1331 adjustable or fixed output voltage version. The difference between these two versions is the configuration of the resistor divider R1/R2. Before using the Demoboard please make sure which chip is on the board and check whether R1/R2 configuration matches the AS1331 version. The marking of the chip can be found printed on the IC soldered on the board. By default an AS1331-AD (adj.) is mounted on the Demoboard. Bill of Materials Ref. Function C1 Input Capacitor 10.0 µF C2 Output Capacitor 22.0 µF L1 Coil 6.8µH R1 FB Voltage divider; for adj. Vout = 3.3V 390 kΩ Description 0805 / X5R / 6.3V / T=0.95mm 1206 / X5R / 16V / T=1.8mm 300mΩ / 0.89A / 3.0x3.0x1.5mm 0805 240 kΩ 0805 FB Voltage divider; for fixed Vout=3.3V 0Ω 0805 R2 not used R3 LBO pull-up resistor 100 kΩ R2 R1 R4 LBI Voltage divider R5 DC/DC Buck-Boost Converter U1 Value 240 kΩ 0805 0805 TDFN 10-pin 3.0x3.0x0.75mm TDFN 10-pin 3.0x3.0x0.75mm ASRU Mfg. Order Nr. Murata GRM219R60J106KE19 Murata GRM31CR61C226KE15 Coilcraft LPS3015-682ML_ 0805 100 kΩ ASRP Manufacturer Austriamicrosystems AG AS1331-BTDT-AD Austriamicrosystems AG AS1331-BTDT-33 Operational sequence This demo board comes with the AS1331. 1. Drive the IC on the demo board only with the recommended settings and values as described in the datasheet. If not present get the datasheet for the AS1331 from www.austriamicrtosystem.com. 2. Connect a +1.8V to +5.5V power supply (Vin “A” and GND “B”). 3. Perform measurements at the measurement points. If there are questions do not hesitate to contact us. See contact information at the end of this manual. www.austriamicrosystems.com Revision 1.01 3-5 AS1331 - Demo Board Manual Buck-Boost Converter Layout of Demo Board Board schematics and layout Figure 3: Schematics Figure 4: Top + Bottom Layer www.austriamicrosystems.com Revision 1.01 4-5 AS1331 - Demo Board Manual Buck-Boost Converter Copyright Copyright © 1997-2010, austriamicrosystems AG, Tobelbaderstraße 30, 8141 Unterpremstätten - Graz, Austria Europe. 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. 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