AS1363
Datasheet - D e t a i l e d D e s c r i p t i o n
8 Detailed Description
The AS1363 is a low-dropout, low-quiescent-current linear regulator specifically designed for battery-powered devices.
The regulator supplies loads of up to 500mA and can deliver a factory-preset output voltage or user-adjustable output
voltage.
The device features a 1.2V reference, error amplifier, P-channel pass transistor, and internal feedback voltage-divider
Additional blocks include an output current limiter, thermal sensor, and shutdown logic.
Figure 15. Block Diagram
V
IN
2.0V to 5.5V
C
IN
1µF
MOSFET
Driver
w/I
LIM
6
On
Off
3
EN
Shutdown
Logic
+
Error
Amplifier
–
1.25V
Reference
5k
Ω
OUT
C
OUT
2.2µF
1
IN
Thermal
Sensor
V
OUT
1.2V to 5.3V
V
OUT
Logic
Supply Voltage
R
POK
100k
Ω
To Controller
2
POK
R
1
5
+
–
93%
VREF
+
–
+
–
100mV
+
–
4
GND
SET
R
2
AS1363-AD
The 1.2V reference is connected to the error amplifier, which compares this reference with the feedback voltage and
amplifies the difference. If the feedback voltage is lower than the reference voltage, the pass-transistor gate is pulled
lower, allowing more current to pass to the output and increases the output voltage. If the feedback voltage is too high,
the pass transistor gate is pulled up, allowing less current to pass to the output.
The output voltage is delivered back through either an internal resistive divider connected to OUT or an external resis-
tor network connected to SET
The comparator examines V
SET/BYP
and selects the feedback path. If
V
SET/BYP
is less than 50mV, the internal feedback path is used and the output is regulated to the factory-preset voltage
Internal P-Channel Pass Transistor
The AS1363 features a P-channel MOSFET pass transistor and consumes only a maximum of 200µA of quiescent
current under heavy loads as well as in dropout.
Shutdown
If pin EN is connected to GND the AS1363 is disabled. In shutdown mode all internal circuits are turned off, reducing
supply current to 30nA (typ.). For normal operation pin EN must be connected to IN. During shutdown, POK is low.
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