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AS1371

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

8 Detailed Description

The AS1371 is a low-dropout, low-quiescent-current linear regulator intended for LDO regulator applications where

output current load requirements range from no load to 400mA. All devices come with fixed output voltage from 0.6V to

3.3V. (see Ordering Information on page 13).

The AS1371 also features a Power-OK output to indicate when the output is within 10% (max) 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

150°C. This is a useful protection when the device is under sustained short circuit conditions.

As illustrated in Figure 13, the devices comprise voltage reference, error amplifier, P-channel MOSFET pass transistor,

Power-OK detect logic, internal voltage divider, current limiter, 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 13. AS1371 - Block Diagram

Output Voltages

Standard products are factory-set with output voltages from 0.6V to 3.3V. 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

EN

GND

POK

OUT

AS1371

Error

Amplifie

r

Trimmable

Reference

Voltage

Shutdown/

Power-On

Control Logic

Thermal

Overload

Protection

Bandgap Voltage

&

Current Reference

-

+

SENSE

Power-OK

Compare

Logic

NMOS

IN