as1331 austriamicrosystems, as1331 Datasheet - Page 2

• Manufacturer Part Number: as1331
• Description: 300ma Buck-boost Synchronous Dc/dc Converters
• Manufacturer: austriamicrosystems

AS1331
Data Sheet - P i n A s s i g n m e n t s
4 Pin Assignments
Figure 2. Pin Assignments (Top View)
Pin Descriptions
Table 1. Pin Descriptions
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PGND
Name
VOUT
SW1
SW2
GND
LBO
VIN
Pin
LBI
EN
NC
FB
Number
Pin
10
11
1
2
3
4
5
6
7
8
9
Output of the Buck/Boost Converter.
Buck/Boost Switch Pin. Connect the inductor from SW1 to SW2
Power Ground. Both GND pins must be connected.
Buck/Boost Switch Pin. Connect the inductor from SW1 to SW2. An
optional Schottky diode can be connected between this pin and VOUT to
increase efficiency.
Input Supply Pin. A minimum 2.2µF capacitor should be placed between
VIN and GND.
Enable Pin. Logic controlled shutdown input.
1 = Normal operation;
0 = Shutdown; quiescent current <1µA.
Low Battery Comperator Input. 1.25V Threshold. May not be left floating.
If connected to GND LBO is working as Output Power okay.
Low Battery Comperator Output. This open-drain output is low when the
voltage on LBI is less than 1.25V.
Ground. Both GND pins must be connected.
Feedback Pin. Feedback input for the adjustable version. Connect a
resistor divider tap to this pin. The output voltage can be adjusted from 2.5V
to 3.3V by: V
Note: For the fixed Output Voltage Version contact this pin to V
Exposed Pad. This pad is not connected internally. It can be used for
ground connection between GND and PGND.
PGND 3
VOUT 1
SW2 2
SW1 4
VIN 5
TDFN (3x3)
AS1331
Revision 1.02
10-pin
OUT
= 1.25V[1 + (R
11
10
9
8
7
6
FB
GND
LBO
LBI
EN
Description
1
/R
2
)]
OUT
.
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