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AS1367

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

8 Detailed Description

The AS1367 is low-dropout, low-quiescent-current linear regulator intended for LDO regulator applications where

output current load requirements range from no load to 150mA. All devices come standard with adjustable output

voltages of 1.2V to 5.0V and fixed output voltages (see Ordering Information on page 13).

The AS1367 also features a Power-OK output to indicate when the output is within 6% of final value, and also an

Enable pin. Shutdown current for the whole regulator is typically 10nA. The device features integrated short-circuit and

over current protection. Under-Voltage lockout prevents erratic operation when the input voltage is slowly decaying

(e.g. in a battery powered application). Thermal Protection shuts down the device when die temperature reaches

160°C. This is a useful protection when the device is under sustained short circuit conditions.

As illustrated in Figure 16, the devices comprise a reference, error amplifier, P-channel MOSFET pass transistor,

Power-OK detect logic, internal voltage divider, current limiter, reverse-battery protection, thermal sensor and

shutdown logic.

The bandgap reference is connected to the inverting input of the error amplifier. The error amplifier compares this

reference with the feedback voltage and amplifies the difference. If the feedback voltage is lower than the reference

voltage, the P-channel MOSFET 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 feeds back through an internal resistor voltage divider connected to pin OUT.

Figure 16. AS1367 - Block Diagram

Output Voltages

Standard products are factory-set with output voltages from 1.2V to 5.0V. A two-digit suffix of the part number identifies

the nominal output (see Ordering Information on page 13). Non-standard devices are available. For more information

contact: http://www.austriamicrosystems.com/contact-us

IN

EN

GND

POK

OUT

AS1367

Error

Amplifier

Trimmable

Reference

Voltage

Shutdown/

Power-On

Control Logic

Reverse-

Battery

Protection

Thermal

Overload

Protection

Bandgap Voltage

&

Current Reference

-

+

Power-OK

Compare

Logic

NMOS