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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

(see Figure 15). Additional blocks include an output current limiter, thermal sensor, and shutdown logic.

Figure 15. Block Diagram

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-

(see Ordering Information on page 13).

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.

2

AS1363-AD

+

–

Shutdown

Logic

+

–

+

–

100mV

+

–

2.2µF

+

–

MOSFET

Driver

Thermal

Sensor

1

IN

6

OUT

3

EN

POK

5

SET

4

GND

1µF

2.0V to 5.5V

Supply Voltage

To Controller

Error

Amplifier

On

Off

1.25V

Reference

1.2V to 5.3V