www.austriamicrosystems.com/LDOs/AS1375

Revision 1.02

6 - 10

AS1375

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

8 Detailed Description

The AS1375 is an low-power and low-quiescent current linear-regulator specifically designed for space-limited applica-

tions. These device can supply loads up to 200mA. As shown in Figure 8, the AS1375 consist of an integrated voltage

reference, error amplifier, P-channel MOSFET pass transistor.

Additional blocks include a current limiter, thermal sensor, and enable logic.

Internal Voltage Reference

The bandgap reference is connected to the error amplifier’s inverting input. 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

pass-transistor gate is pulled low. This allows 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 high, allowing less current to pass to the output.

Figure 8. AS1375 - Block Diagram

Current Limit

The AS1375 include a current limiting circuitry to monitor and control the P-channel MOSFET pass transistor’s gate

voltage, thus limiting the device output current to 300mA.

Note: See Table 3 on page 4 for the min and max current limits. The output can be shorted to ground indefinitely

without causing damage to the device.

Thermal Protection

exceeds +160ºC, the thermal sensor signals the shutdown logic, turning off the P-channel MOSFET pass transistor

and allowing the device to cool down. The thermal sensor turns the pass transistor on again after the device’s junction

temperature drops by 20ºC, resulting in a pulsed output during continuous thermal-overload conditions.

Note: Thermal protection is designed to protect the devices in the event of fault conditions. For continuous operation,

do not exceed the absolute maximum junction temperature rating of +150ºC.

EN

GND

OUT

AS1375

-

+

Overcurrent

Protection

Voltage

and

Current Reference

Enable Con-

trol Logic

Thermal

Protection

IN