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
C
D
VIN
GND
EN
VOUT
Supply Voltage
Ground
Enable Connector
Output Voltage
Supply voltage ranging from 1.8V to 5.5V
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
Info
E
F
G
H
I
J
K
L
M
VIN
SW1
SW2
VOUT
EN
FB
GND
LBO
LBI
Supply Voltage
External Inductor
Output Voltage
Enable Voltage
Feedback Voltage
Ground
Low Battery Output
Low Battery Input
Measurement Points
ON: The AS1331 is on.
N
EN
Enable
OFF; The AS1324 is off and the current
into Vin is <1µA (typ).
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
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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
Low Battery Output
VIN: Signal on LBO is connected via R3 to
VIN.
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.
C1
C2
L1
R1
R2
R1
R2
R3
R4
R5
U1
Function
Input Capacitor
Output Capacitor
Coil
FB Voltage divider;
for adj. Vout = 3.3V
FB Voltage divider;
for fixed Vout=3.3V
LBO pull-up resistor
LBI Voltage divider
DC/DC Buck-Boost
Converter
Value
10.0 µF
22.0 µF
6.8µH
390 kΩ
240 kΩ
0
Ω
not used
100 kΩ
240 kΩ
100 kΩ
ASRP
ASRU
0805
0805
0805
TDFN 10-pin
3.0x3.0x0.75mm
TDFN 10-pin
3.0x3.0x0.75mm
Description
0805 / X5R / 6.3V /
T=0.95mm
1206 / X5R / 16V /
T=1.8mm
300mΩ / 0.89A /
3.0x3.0x1.5mm
0805
0805
0805
Manufacturer
Murata
Murata
Coilcraft
Mfg. Order Nr.
GRM219R60J106KE19
GRM31CR61C226KE15
LPS3015-682ML_
Austriamicrosystems AG AS1331-BTDT-AD
Austriamicrosystems AG AS1331-BTDT-33
Operational sequence
This demo board comes with the AS1331.
1.
2.
3.
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.
Connect a +1.8V to +5.5V power supply (Vin
“A”
and GND
“B”).
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.
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AS1331 - Demo Board Manual
Buck-Boost Converter
Layout of Demo Board
Board schematics and layout
Figure 3: Schematics
Figure 4: Top + Bottom Layer
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Revision 1.01
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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.
Disclaimer
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 life-sustaining 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
Tobelbaderstraße 30
A-8141 Unterpremstätten - Graz, 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
www.austriamicrosystems.com
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