AS1312
Datasheet - Application Information
9 Application Information
The AS1312 is available with fixed output voltages from 2.5V to 5.0V in 50mV steps.
Figure 11. AS1312 - Block Diagram
0.7 to 5.0V
6.8µH
Zero
2.5V to 5.0V
Output
Input
Crossing
LX
VOUT
Detector
C
22µF
OUT
C
22µF
IN
Startup
Circuitry
Driver
and
R
3
VIN
LBI
Control
Logic
–
+
LBO
REF
Imax
Detection
V
REF
AS1312
EN
C
REF
100nF
GND
9.1 AS1312 Features
Shutdown.
The part is in shutdown mode while the voltage at pin EN is below 0.1V and is active when the voltage is higher than 0.7V.
Note: EN can be driven above VIN or VOUT, as long as it is limited to less than 5.0V.
Output Disconnect.
During shutdown VOUT is going to 0V and no current from the input source is running through the device.
Feedthrough Mode.
If the input voltage is higher than the output voltage (and the AS1312 is enabled) the supply voltage is connected to the load through the device.
To guarantee a proper function of the AS1312 it is not allowed that the supply exceeds the maximum allowed input voltage (5.0V).
In this feedthrough mode the quiescent current is 35µA (typ.). The device goes back into step-up mode when the output voltage is 4% (typ.)
below VOUTNOM
.
www.ams.com/DC-DC_Step-Up
Revision 1.12
11 - 20
AMSCO [ AMS(艾迈斯) ]
