www.ams.com/DC-DC_Step-Up/AS1324 Revision 1.06 1 - 21
AS1324
1.5MHz, 600mA Synchronous DC/DC Converter
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
C
OUT
10µF
C
IN
10µF
GND
2
V
IN
= 2.7V to 5.5V
V
OUT
= 1.8V, 600mA
4.7µH
1
EN
5
VOUT
4
VIN
3
SW
5 VOUT
AS1324-18
4 VIN
2
GND
3SW
1
EN
