www.ams.com/DC-DC_Step-Down

Revision 1.10

1 - 16

AS1346-49

Dual Step-Down Converter with Battery Monitoring

1 General Description

The AS1346, AS1347, AS1348, AS1349 family is a high-efficiency,

constant-frequency dual buck converter available with fixed voltage

versions. The device provides two independent DC/DC Converters

with output currents between 0.5A and 1.2A. The wide input voltage

range (2.7V to 5.5V), automatic powersave mode and minimal

external component requirements make the AS134x family perfect

for SSD and many other battery-powered applications.

In shutdown mode the typical supply current decreases to ≤1μA.

The highly efficient duty cycle (100%) provides low dropout

operation, prolonging battery life in portable systems.

An internal synchronous switching scheme increases efficiency and

eliminates the need for an external Schottky diode. The fixed

switching frequency (2.0MHz) allows the use of small surface mount

inductors.

The integrated monitoring function can be configured that either the

output voltage (Power Okay function ) or the input voltage (Battery

Monitoring Function) can be supervised.

The AS1346-49 is available in a 12-Pin TDFN 3x3mm package.

2 Key Features



High Efficiency: Up to 95%



Output Current: see Table 1



Input Voltage Range: 2.7V to 5.5V



Output Voltage Range: 1.2V to 3.6V (available in 100mV steps)



Constant Frequency Operation: 2.0MHz



180º Out of Phase Operation



Low Battery Detection



Low Dropout Operation: 100% Duty Cycle



Shutdown Mode Supply Current:

1μA



No Schottky Diode Required



Output Disconnect in Shutdown



Non standard variants available within two weeks



12-Pin TDFN 3x3mm Package

3 Applications

The device is ideal for SSD applications, 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. Available Products

Devices

AS1346

1.2A

0.5A

AS1347

0.5A

0.5A

AS1348

0.5A

0.95A

AS1349

1.2A

1.2A

AS1346

2.7V to 5.5V

3.3V 1200mA

Figure 1. AS1346 - Typical Application Diagram with POK Function

SW1

1.8V 500mA

FB1

FB2

SW2

AGND

EN2

PVIN

VDD

EN1

LBO

LBI

L1 = 3.3μH

POK Function

L2 = 3.3μH

PVIN

PGND