AS1331
Datasheet - P i n A s s i g n m e n t s
4 Pin Assignments
Figure 2. Pin Assignments (Top View)
VOUT 1
SW2 2
PGND 3
SW1 4
VIN 5
11
10 FB
9 GND
AS1331
8 LBO
7 LBI
6 EN
Pin Descriptions
Table 1. Pin Descriptions
Pin
Name
VOUT
SW1
PGND
SW2
VIN
EN
LBI
LBO
GND
Pin
Number
1
2
3
4
5
6
7
8
9
Description
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
OUT
= 1.25V[1 + (R
1
/R
2
)]
Note:
For the fixed Output Voltage Version contact this pin to V
OUT
.
Exposed Pad.
This pad is not connected internally. It can be used for
ground connection between GND and PGND.
FB
10
NC
11
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