AS1347-BTDT-3310

AS1347-BTDT-3310 Datasheet

AS1346-49

Part	Datasheet
AS1347-BTDT-3310	AS1347-BTDT-3310 (pdf)

Related Parts	Information
AS1349-BTDT-3312	AS1349-BTDT-3312
AS1348-BTDT3312	AS1348-BTDT3312
AS1347-BTDT-1812	AS1347-BTDT-1812
AS1349-BWLT3312	AS1349-BWLT3312
AS1346-BTDT3318	AS1346-BTDT3318

PDF Datasheet Preview
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 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 Available Products Devices IOUT1 IOUT2 AS1346 1.2A 0.5A AS1347 0.5A 0.5A AS1348 0.5A 0.95A AS1349 1.2A 1.2A The AS1346-49 is available in a 12-Pin TDFN 3x3mm package. Figure AS1346 - Typical Application Diagram with POK Function 2 Key Features Efficiency Up to 95% Current see Table 1 Voltage Range 2.7V to 5.5V Voltage Range 1.2V to 3.6V available in 100mV steps Frequency Operation 2.0MHz Out of Phase Operation Battery Detection Dropout Operation 100% Duty Cycle Mode Supply Current Schottky Diode Required Disconnect in Shutdown standard variants available within two weeks 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 powerconsumption requirements. VIN 2.7V to 5.5V PVIN AS1346 L1 = 3.3uH SW1 FB1 L2 = 3.3uH SW2 FB2 VOUT1 3.3V 1200mA COUT1 VOUT2 1.8V 500mA COUT2 POK Function AGND PGND 1 - 16 AS1346-49 Datasheet - Pin Assignments 4 Pin Assignments 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 4.7uF 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 supply current. This pin should not be left floating. Feedback Pin 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 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 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 higher than 1.2V or - LBI is connected to GND and VOUT1 is below of its nominal value. 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 this pin to VOUT2. The output can be factory set from 1.2V to 3.6V. For further information see Ordering Information on page Supply Connector. Connect this pin to PVIN Switch Node2 Connection to Inductor. This pin connects to the drains of the internal main and synchronous power MOSFET switches. Exposed Pad. The exposed pad must be connected to AGND. Ensure a good electrical connection to the PCB to achieve optimal thermal performance. 2 - 16 AS1346-49 Datasheet - Absolute Maximum Ratings 5 Absolute Maximum Ratings Stresses beyond those listed in Table 3 may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in Electrical Characteristics on page 4 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table Absolute Maximum Ratings Parameter Electrical Parameters Units Notes VDD, PVIN to AGND PGND to AGND EN, FB SW AGND - VDD + PGND - PVIN + 7.0V max PVIN to VDD Electrostatic Discharge Human Body Model Temperature Ranges and Storage Conditions Junction Temperature TJ-MAX Storage Temperature Range +150 +150 Norm MIL 883 E method 3015 Package Body Temperature The reflow peak soldering temperature body temperature specified is in accordance with IPC/ JEDEC J-STD-020 “Moisture/Reflow Sensitivity +260 Classification for Non-Hermetic Solid State Surface Mount Devices”. The lead finish for Pb-free leaded packages is matte tin 100% Sn . Humidity non-condensing Moisture Sensitive Level Represents a max. floor life time of unlimited 3 - 16 AS1346-49 Datasheet - Electrical Characteristics 6 Electrical Characteristics The AS1346, AS1347, AS1348, AS1349 family is a high-efficiency buck converter that uses a constant-frequency current-mode architecture. The device contains two internal MOSFET switches and is available with a fixed output voltage see Ordering Information on page Figure AS1346 - Block Diagram PVIN AS1346 Current Sense PWM COMP Error Amplifier Mosfet Soft Start Control Logic Main Control Shutdown Control PVIN Oscillator FB2 Current Sense PWM COMP Error Amplifier Mosfet Soft Start Control Logic Power-OK Compare Logic AGND PGND 9 - 16 AS1346-49 Datasheet - Detailed Description Main Control Loop During normal operation, the internal top power MOSFET is turned on each cycle when the oscillator sets the RS latch. This switch is turned off when the current comparator resets the RS latch. The peak inductor current IPK at which ICOMP resets the RS latch, is controlled by the error amplifier. When ILOAD increases, VFB decreases slightly relative to the internal 0.6V reference, causing the error amplifier’s output voltage to increase until the average inductor current matches the new load current. Short-Circuit Protection The short-circuit protection turns off the power switches as long as the short is applied. When the short is removed the device is continuing normal operation. Dropout Operation The AS1346, AS1347, AS1348, AS1349 is working with a low input-to-output voltage difference by operating at 100% duty cycle. In this state, the PMOS is always on. This is particularly useful in battery-powered applications with a 3.3V output. The AS1346, AS1347, AS1348, AS1349 allows the output to follow the input battery voltage as it drops below the regulation voltage. The quiescent current in this state is reduced to a minimal value, which aids in extending battery life. This dropout 100% duty-cycle operation achieves long battery life by taking full advantage of the entire battery range. The input voltage requires maintaining regulation and is a function of the output voltage and the load. The difference between the minimum input voltage and the output voltage is called the dropout voltage. The dropout voltage is therefore a function of the on-resistance of the internal PMOS RDS ON PMOS and the inductor resistance DCR and this is proportional to the load current. Note At low VIN values, the RDS ON of the P-channel switch increases see Electrical Characteristics on page Therefore, power dissipation should be taken in consideration. Shutdown Connecting EN to GND or logic low places the AS1346, AS1347, AS1348, AS1349 in shutdown mode and reduces the supply current to 0.1uA. In shutdown the control circuitry and the internal NMOS and PMOS turn off and SW becomes high impedance disconnecting the input from the output. The output capacitance and load current determine the voltage decay rate. For normal operation connect EN to VIN or logic high. Note Pin EN should not be left floating. Power-OK and Low-Battery-Detect Functionality LBO goes low in startup mode as well as during normal operation if, - The voltage at the LBI pin is above LBI threshold 1.2V . This can be used to monitor the battery voltage. - LBI pin is connected to GND and VOUT1 is below of its nominal value. LBO works as a power-OK signal in this case. The LBI pin can be connected to a resistive-divider to monitor a particular definable voltage and compare it with a 1.2V internal reference. If LBI is connected to GND see Figure 1 on page 1 an internal resistive-divider is activated and connected to the output. Therefore, the Power-OK functionality can be realized with no additional external components. Datasheet - Ordering Information 11 Ordering Information The device is available as the standard products listed below. Table Ordering Information Ordering Code AS1346-BTDT-3318 Marking Channel Vout ASSL OUT1 3.3V OUT2 1.8V AS1347-BTDT-1812 ASU6 OUT1 1.8V OUT2 1.2V AS1347-BTDT-3310 ASU7 OUT1 3.3V OUT2 1.0V AS1348-BTDT-3312 ASTZ OUT1 3.3V OUT2 1.2V AS1346-BTDT-xxyy1 OUT1 OUT2 OUT1 AS1347-BTDTxxyy1 OUT2 OUT1 AS1348-BTDTxxyy1 OUT2 OUT1 AS1349-BTDTxxyy1 OUT2 Iout 1.2A 0.5A 0.5A 0.5A 0.5A 0.5A 0.5A 0.95A 1.2A 0.5A 0.5A 0.5A 0.5A 0.95A 1.2A 1.2A Dual Step-Down Converter with Battery Monitoring Dual Step-Down Converter with Battery Monitoring Dual Step-Down Converter with Battery Monitoring Dual Step-Down Converter with Battery Monitoring Dual Step-Down Converter with Battery Monitoring Dual Step-Down Converter with Battery Monitoring Dual Step-Down Converter with Battery Monitoring Dual Step-Down Converter with Battery

PDF Datasheet Preview

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 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 Available Products

Devices

IOUT1

IOUT2

AS1346
1.2A
0.5A

AS1347
0.5A
0.5A

AS1348
0.5A
0.95A

AS1349
1.2A
1.2A

The AS1346-49 is available in a 12-Pin TDFN 3x3mm package. Figure AS1346 - Typical Application Diagram with POK Function
2 Key Features

Efficiency Up to 95% Current see Table 1 Voltage Range 2.7V to 5.5V Voltage Range 1.2V to 3.6V available in 100mV steps Frequency Operation 2.0MHz Out of Phase Operation Battery Detection Dropout Operation 100% Duty Cycle Mode Supply Current Schottky Diode Required Disconnect in Shutdown standard variants available within two weeks 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 powerconsumption requirements.

VIN 2.7V to 5.5V

PVIN

AS1346

L1 = 3.3uH SW1 FB1 L2 = 3.3uH SW2 FB2

VOUT1 3.3V 1200mA COUT1

VOUT2 1.8V 500mA COUT2

POK Function

AGND

PGND
1 - 16

AS1346-49

Datasheet - Pin Assignments
4 Pin Assignments
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 4.7uF 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 supply current. This pin should not be left floating. Feedback Pin 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 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 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 higher than 1.2V or - LBI is connected to GND and VOUT1 is below of its nominal value. 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 this pin to VOUT2. The output can be factory set from 1.2V to 3.6V. For further information see Ordering Information on page Supply Connector. Connect this pin to PVIN

Switch Node2 Connection to Inductor. This pin connects to the drains of the internal main and synchronous power MOSFET switches. Exposed Pad. The exposed pad must be connected to AGND. Ensure a good electrical connection to the PCB to achieve optimal thermal performance.
2 - 16

AS1346-49

Datasheet - Absolute Maximum Ratings
5 Absolute Maximum Ratings

Stresses beyond those listed in Table 3 may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in Electrical Characteristics on page 4 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

Table Absolute Maximum Ratings

Parameter Electrical Parameters

Units

Notes

VDD, PVIN to AGND

PGND to AGND

EN, FB SW

AGND - VDD +

PGND - PVIN +
7.0V max

PVIN to VDD Electrostatic Discharge

Human Body Model

Temperature Ranges and Storage Conditions

Junction Temperature TJ-MAX

Storage Temperature Range
+150
+150

Norm MIL 883 E method 3015

Package Body Temperature

The reflow peak soldering temperature body
temperature specified is in accordance with IPC/

JEDEC J-STD-020 “Moisture/Reflow Sensitivity
+260

Classification for Non-Hermetic Solid State

Surface Mount Devices”.

The lead finish for Pb-free leaded packages is
matte tin 100% Sn .

Humidity non-condensing

Moisture Sensitive Level

Represents a max. floor life time of unlimited
3 - 16

AS1346-49

Datasheet - Electrical Characteristics
6 Electrical Characteristics
The AS1346, AS1347, AS1348, AS1349 family is a high-efficiency buck converter that uses a constant-frequency current-mode architecture. The device contains two internal MOSFET switches and is available with a fixed output voltage see Ordering Information on page Figure AS1346 - Block Diagram

PVIN

AS1346

Current Sense

PWM COMP

Error Amplifier

Mosfet

Soft Start

Control Logic

Main Control

Shutdown Control

PVIN

Oscillator FB2

Current Sense

PWM COMP

Error Amplifier

Mosfet

Soft Start

Control Logic

Power-OK

Compare

Logic

AGND

PGND
9 - 16

AS1346-49

Datasheet - Detailed Description

Main Control Loop

During normal operation, the internal top power MOSFET is turned on each cycle when the oscillator sets the RS latch. This switch is turned off when the current comparator resets the RS latch. The peak inductor current IPK at which ICOMP resets the RS latch, is controlled by the error amplifier. When ILOAD increases, VFB decreases slightly relative to the internal 0.6V reference, causing the error amplifier’s output voltage to increase until the average inductor current matches the new load current.

Short-Circuit Protection

The short-circuit protection turns off the power switches as long as the short is applied. When the short is removed the device is continuing normal operation.

Dropout Operation

The AS1346, AS1347, AS1348, AS1349 is working with a low input-to-output voltage difference by operating at 100% duty cycle. In this state, the PMOS is always on. This is particularly useful in battery-powered applications with a 3.3V output.

The AS1346, AS1347, AS1348, AS1349 allows the output to follow the input battery voltage as it drops below the regulation voltage. The quiescent current in this state is reduced to a minimal value, which aids in extending battery life. This dropout 100% duty-cycle operation achieves long battery life by taking full advantage of the entire battery range.

The input voltage requires maintaining regulation and is a function of the output voltage and the load. The difference between the minimum input voltage and the output voltage is called the dropout voltage. The dropout voltage is therefore a function of the on-resistance of the internal PMOS RDS ON PMOS and the inductor resistance DCR and this is proportional to the load current.

Note At low VIN values, the RDS ON of the P-channel switch increases see Electrical Characteristics on page Therefore, power dissipation should be taken in consideration.

Shutdown

Connecting EN to GND or logic low places the AS1346, AS1347, AS1348, AS1349 in shutdown mode and reduces the supply current to 0.1uA. In shutdown the control circuitry and the internal NMOS and PMOS turn off and SW becomes high impedance disconnecting the input from the output. The output capacitance and load current determine the voltage decay rate. For normal operation connect EN to VIN or logic high.

Note Pin EN should not be left floating.

Power-OK and Low-Battery-Detect Functionality LBO goes low in startup mode as well as during normal operation if,
- The voltage at the LBI pin is above LBI threshold 1.2V . This can be used to monitor the battery voltage. - LBI pin is connected to GND and VOUT1 is below of its nominal value. LBO works as a power-OK signal in this case. The LBI pin can be connected to a resistive-divider to monitor a particular definable voltage and compare it with a 1.2V internal reference. If LBI is connected to GND see Figure 1 on page 1 an internal resistive-divider is activated and connected to the output. Therefore, the Power-OK functionality can be realized with no additional external components.
Datasheet - Ordering Information
11 Ordering Information

The device is available as the standard products listed below.
Table Ordering Information
Ordering Code AS1346-BTDT-3318

Marking Channel Vout

ASSL

OUT1 3.3V OUT2 1.8V

AS1347-BTDT-1812

ASU6

OUT1 1.8V OUT2 1.2V

AS1347-BTDT-3310

ASU7

OUT1 3.3V OUT2 1.0V

AS1348-BTDT-3312

ASTZ

OUT1 3.3V OUT2 1.2V

AS1346-BTDT-xxyy1

OUT1

OUT2

OUT1

AS1347-BTDTxxyy1

OUT2

OUT1

AS1348-BTDTxxyy1

OUT2

OUT1

AS1349-BTDTxxyy1

OUT2

Iout 1.2A 0.5A 0.5A 0.5A 0.5A 0.5A 0.5A 0.95A 1.2A 0.5A 0.5A 0.5A 0.5A 0.95A 1.2A 1.2A

Dual Step-Down Converter with Battery

Monitoring

Dual Step-Down Converter with Battery

Monitoring

Dual Step-Down Converter with Battery

Monitoring

Dual Step-Down Converter with Battery

Monitoring

Dual Step-Down Converter with Battery

Monitoring

Dual Step-Down Converter with Battery

Monitoring

Dual Step-Down Converter with Battery

Monitoring

Dual Step-Down Converter with Battery

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Datasheet ID: AS1347-BTDT-3310 519609