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AS1364

Datasheet - D e t a i l e d D e s c r i p t i o n

8 Detailed Description

The AS1364 output voltage is factory-trimmed or is adjustable from +1.2 to +5V, and is guaranteed to supply 1A of out-

put current. The device consists of a +1.20V internal reference, error amplifier, MOSFET driver, P-channel pass tran-

sistor, internal feedback voltage-divider and a comparator (see Figure 16).

Figure 16. AS1364 - Block Diagram

The +1.20V reference is connected to the inverting input of the error amplifier, which compares this reference with the

selected feedback voltage and amplifies the difference.

The MOSFET driver reads the error signal and applies the appropriate drive to the P-channel transistor. If the feedback

voltage is lower than the reference, the pass transistor gate is pulled lower, allowing more current to pass increasing

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.

to go low.

The output voltage is fed back through either an internal resistor-divider connected to OUT or an external resistor net-

50mV, the internal feedback path is used and the output is regulated to the factory-preset voltage.

AS1364

+

–

Shutdown

Logic

+

–

+

–

100mV

+

–

4.7µF

+

–

MOSFET

Driver

Thermal

Sensor

4

IN

6

OUT

2

EN

1

POK

7

SET/BYP

8

GND

4.7µF

2.0V to 5.5V

Supply Voltage

To Controller

Error

Amplifier

On

Off

1.20V

Reference

1.2V to 5.0V

3

IN

5

OUT