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PDF AS1349 Data sheet ( Hoja de datos )
| Número de pieza | AS1349 | |
| Descripción | (AS1346 - AS1349) Dual Step Down Converter | |
| Fabricantes | Austin Semiconductor | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de AS1349 (archivo pdf) en la parte inferior de esta página. Total 15 Páginas | ||
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Datasheet
www.DataSheet4U.com
AS1346, AS1347, AS1348, AS1349
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 pro-
vides 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.
Table 1. Available Products
Devices
IOUT1
AS1346
1.2A
AS1347
0.5A
AS1348
0.5A
AS1349
1.2A
IOUT2
0.5A
0.5A
0.95A
1.2A
The AS1346 is available in a 12-Pin TDFN 3x3mm pack-
age.
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
! 180° 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 commu-
nication 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.
Figure 1. AS1346 - Typical Application Diagram with POK Function
VIN
2.7V to 5.5V
CIN
PVIN
PVIN
VDD
EN1
EN2
AS1346
L1 = 3.3µH
SW1
VOUT1
3.3V 1200mA
COUT1
FB1 L2 = 3.3µH
SW2
VOUT2
1.8V 500mA
COUT2
FB2
LBO
POK Function
LBI AGND
PGND
www.austriamicrosystems.com/DC-DC_Step-Down/AS1346
Revision 1.01
1 - 15
1 page  
AS1346, AS1347, AS1348, AS1349
Datasheet - Electrical Characteristics
www.DataSheet4U.com
Table 4. Electrical Characteristics
Symbol
Parameter
Enable
VIH,EN
Logic high input threshold
VIH,EN
Logic low input threshold
Low Battery & Power-OK
VLBI LBI Threshold
LBI Hysteresis
LBI Leakage Current
LBO Voltage Low2
LBO Leakage Current
Power-OK Threshold
Conditions
Falling Edge
LBI = 5V, TA = 25°C
ILBO = 0.1mA
LBO = 5V, TA = 25°C
LBI = 0V, Falling Edge
Min Typ Max Units
1.2 V
0.5V V
1.16 1.2 1.24 V
10 mV
1 nA
0.05 V
1 nA
85 88 90 %
1. The dynamic supply current is higher due to the gate charge delivered at the switching frequency. The Quies-
cent Current is measured while the DC-DC Converter is not switching.
2. LBO goes low in startup mode as well as during normal operation if:
1) The voltage at the LBI pin is below LBI threshold.
2) The voltage at the LBI pin is below 0.1V and VOUT is below 92.5% of its nominal value.
Note: All limits are guaranteed. The parameters with min and max values are guaranteed with production tests or
SQC (Statistical Quality Control) methods.
www.austriamicrosystems.com/DC-DC_Step-Down/AS1346
Revision 1.01
5 - 15
5 Page 
AS1346, AS1347, AS1348, AS1349
Datasheet - Detailed Description
www.DataSheet4U.com
In case of the LBI pin is connected to GND, an internal resistor-divider network is activated and compares the output
voltage with a 92.5% voltage threshold (see AS1346 - Typical Application Diagram with POK Function on page 1). For
this particular Power-OK application, no external resistive components (R1 and R2) are necessary.
Figure 18. Typical Application Diagram with adjustable Battery Monitoring
VIN
4.5V to 5.5V
CIN
R1
R2
PVIN
PVIN
VDD
EN1
AS1346
L1 = 3.3µH
SW1
FB1 L2 = 3.3µH
SW2
FB2
VOUT1
3.3V 1200mA
COUT1
VOUT2
1.8V 500mA
COUT2
R3
EN2
LBO
LBI AGND
PGND
Thermal Shutdown
Due to its high-efficiency design, the AS1346 will not dissipate much heat in most applications. However, in applica-
tions where the AS1346 is running at high ambient temperature, uses a low supply voltage, and runs with high duty
cycles (such as in dropout) the heat dissipated may exceed the maximum junction temperature of the device.
As soon as the junction temperature reaches approximately 150ºC the AS1346 goes in thermal shutdown. In this mode
the internal PMOS & NMOS switch are turned off. The device will power up again, as soon as the temperature falls
below +140°C again.
www.austriamicrosystems.com/DC-DC_Step-Down/AS1346
Revision 1.01
11 - 15
11 Page | ||
| Páginas | Total 15 Páginas | |
| PDF Descargar | [ Datasheet AS1349.PDF ] | |
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