Maker : Austin Semiconductor
Part No. : AS1349

  Datasheet PDF : AS1349.pdf
  Cross Reference : AS1349 Cross Reference
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Shortcut : AS1340  AS1341  AS1343  AS1344  AS1344  AS1346  AS1347  AS1348  AS1349 

Product Information

Datasheet AS1346, AS1347, AS1348, AS1349 D u a l St e p - D o w n C o n v e r t e r w i t h B a t t e r y M o n i t o r i n g www.DataSheet4U.com 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 batterypowered applications. 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 ! ! ! ! ! ! ! ! ! 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 AS1346 AS1347 AS1348 AS1349 IOUT1 1.2A 0.5A 0.5A 1.2A IOUT2 0.5A 0.5A 0.95A 1.2A 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. The AS1346 is available in a 12-Pin TDFN 3x3mm package. Figure 1. AS1346 - Typical Application Diagram with POK Function VIN 2.7V to 5.5V L1 = 3.3µH CIN PVIN PVIN VDD EN1 EN2 LBI PGND SW1 FB1 SW2 FB2 LBO AGND POK Function VOUT1 3.3V 1200mA COUT1 L2 = 3.3µH COUT2 AS1346 VOUT2 1.8V 500mA www.austriamicrosystems.com/DC-DC_Step-Down/AS1346 Revision 1.01 1 - 15 AS1346, AS1347, AS1348, AS1349 Datasheet - P i n A s s i g n m e n t s www.DataSheet4U.com 4 Pin Assignments Figure 2. Pin Assignments (Top View) SW1 1 PVIN 2 EN1 3 FB1 4 EN2 5 LBO 6 13 12 SW2 11 PVIN 10 VDD 9 FB2 8 AGND 7 LBI AS1346 Pin Descriptions Table 2. Pin Descriptions Pin Number 1 2, 11 Pin Name SW1 PVIN Description Switch Node1 Connection to Inductor. This pin connects to the drains of the internal main and synchronous power MOSFET switches. Power Supply Connector. This pin must be closely decoupled to PGND with a ≥ 4.7µF ceramic capacitor. Enable1 Input. Driving this pin above 1.2V enables VOUT1. Driving this pin below 0.5V puts the device in shutdown mode. In shutdown mode all functions are disabled, drawing ≤1µA supply current. This pin should not be left floating. Feedback Pin 1. Feedback input to the error amplifier, connect this pin to VOUT1. The output can be factory set from 1.2V to 3.6V. For further information see Ordering Information on page 14. Enable2 Input. Driving this pin above 1.2V enables VOUT2. Driving this pin below 0.5V puts the device in shutdown mode. In shutdown mode all functions are disabled, drawing ≤1µA supply current. This pin should not be left floating. Low Battery Comperator Output. This open-drain output is low when the voltage on LBI is less than 1.2V. Low Battery Comperator Input. 1.2V Threshold. May not be left floating. If connected to GND, LBO is working as Output Power Okay for VOUT1. Analog Ground. Feedback 2 Pin. Feedback input to the error amplifier, connect...

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