www.ams.com/DC-DC_Step-Up/AS1324

Revision 1.06

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1 General Description

The AS1324 is a high-efficiency, constant-frequency synchronous

buck converter available in adjustable- and fixed-voltage versions.

The wide input voltage range (2.7V to 5.5V), automatic powersave

mode and minimal external component requirements make the

AS1324 perfect for any single Li-Ion battery-powered application.

Typical supply current with no load is 30µA and decreases to

≤1µA

in shutdown mode.

The AS1324 is available as the standard versions listed in Table 1.

An internal synchronous switch increases efficiency and eliminates

the need for an external Schottky diode. The internally fixed

switching frequency (1.5MHz) allows for the use of small surface

mount external components.

Very low output voltages can be delivered with the internal 0.6V

feedback reference voltage.

The AS1324 is available in a 5-pin TSOT-23 package.

Figure 1. Typical Application Diagram – High Efficiency Step

Down Converter

2 Key Features

High Efficiency: Up to 96%

Output Current: 600mA

Input Voltage Range: 2.7V to 5.5V

Constant Frequency Operation: 1.5MHz

Variable- and Fixed-Output Voltages

No Schottky Diode Required

Automatic Powersave Operation

Low Quiescent Current: 30µA

Internal Reference: 0.6V

Shutdown Mode Supply Current:

≤1µA

Thermal Protection

5-pin TSOT-23 Package

3 Applications

The device is ideal for mobile communication devices, laptops and

PDAs, ultra-low-power systems, threshold detectors/discriminators,

telemetry and remote systems, medical instruments, or any other

space-limited application with low power-consumption requirements.

Table 1. Standard Versions

Model

Output Voltage

AS1324-AD

Adjustable via External Resistors

AS1324-12

Fixed: 1.2V

AS1324-15

Fixed: 1.5V

AS1324-18

Fixed: 1.8V

AS1324-18

10µF

10µF

GND

2

4.7µH

1

EN

5

VOUT

4

VIN

3

SW

5 VOUT

AS1324-18

4 VIN

2

GND

3

SW

1

EN