AMS4155 [ADMOS]

2A OUTPUT PWM BUCK CONVERTER; 2A输出PWM降压转换器


型号：	AMS4155
厂家：	ADVANCED MONOLITHIC SYSTEMS
描述：	2A OUTPUT PWM BUCK CONVERTER 2A输出PWM降压转换器转换器输出元件
文件：	总6页 (文件大小：389K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

Advanced

Monolithic

Systems

AMS4155

2A OUTPUT PWM BUCK CONVERTER

RoHS compliant

FEATURES

APPLICATIONS

• Stable with low ESR Output Ceramic Capacitors

• Up to 95% Efficiency

• 2A Continuous Output Current

• Wide 4.75V to 20V Operating Input Range

• Fixed 480kHz Frequency

• Battery Chargers

• Portable (Notebook) Computers

• Industrial power supply

• Point of regulation for high performance electronics

• Consumer Electronics

• Thermal Shutdown

• Cycle-by-cycle + hiccup Over Current Protection

• Under Voltage Lockout

• Frequency Synchronization Input

• Operating Temperature: -40°C to 125°C

• Available in an 8-Pin SO Package

• Audio Power Amplifiers

• Distributed Power Systems

• Pre-Regulator for Linear Regulators

• LCD TVs and LCD monitors

GENERAL DESCRIPTION

The AMS4155 is a monolithic step down switch mode converter with a built in internal power Switch Transistor. It achieves 2A

continuous output current over a wide input supply range with excellent load and line regulation.

Current mode operation provides fast transient response and eases loop stabilization. Fault condition protection includes cycle-

by-cycle current limiting and thermal shutdown. In shutdown mode the regulator draws 17µA of supply current.

ORDERING INFORMATION

OUTPUT

PACKAGE TYPE

TEMP. RANGE

VOLTAGE 8 Lead SOIC

Adjustable AMS4155S

-25°C to 125°C

TYPICAL APPLICATION

PIN CONNECTIONS

8L SOIC

INPUT

1µF

470µF/

10µF CER

VIN

SO Package (S)

BST

10 µH

OUTPUT

5V/3A

OFF

SYNC

BST

AMS4155

B230A

SYNC

F/B

COMP

VIN

COMP

GND

30kΩ

10kΩ

10nF

GND

40µF

ceramic

5kΩ

Top View

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS4155

PIN DESCRIPTION

Pin Number

NAME

DESCRIPTION

SYNC

Synchronization Input. This pin is used to synchronize the internal oscillator frequency to

an external source. Leave SYNC unconnected or connect to GND if unused.

BST

Bootstrap. This capacitor is needed to drive the power switch above the supply voltage. It

is connected between LX and BST pins to form a floating supply across the power switch

driver. The voltage across Cbst is about 5V and is supplied by the internal Vcc supply

when LX pin voltage is low.

VIN

Supply Voltage. The AMS4155 operates from a+4.75V to +23V unregulated input. Cin is

needed to prevent large voltage spikes from appearing at the input power supply.

This connects the inductor to the internal Switch

GND

Ground Pin connected to PCB ground plane. This pin is also the ground for internal voltage

reference.

Feedback. A resistor network of two resistors is used to set-up the output voltage connected

between Output to GND. The node between the two resistors is connected to Feedback pin.

COMP

Compensation. This node is the output of the transconductance error amplifier and the

input to the current comparator. Frequency compensation is done at this node by

connecting a series R-C to ground.

ENABLE

Enable. A voltage greater than 2.495V at this pin enables device operation.

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS4155

ABSOLUTE MAXIMUM RATINGS

V_IN

28V

COMP

SYNC

-1V to +28V

-0.3V to +6V

-0.3v to +6V

F/B

BST

-0.3V to +6V

VLX + 6V

Junction Temperature

Storage Temperature

Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds

+150°C

-65°C to +150°C

260°C

ELECTRICAL CHARACTERISTICS

Electrical Characteristics at T_A= 25 °C and VIN=12V (unless otherwise noted).

AMS4155

Typ.

PARAMETER

TEST CONDITIONS

Units

Max.

Min.

Feedback Voltage

4.75V ≤ V_IN≤ 20V, V_COMP< 2V

1.215

1.255

1.285

Switch On Resistance

Switch Leakage

Current Limit ⁽¹⁾

0.18

Ω

µA

_EN= 0V; VLX = 0V

3.4

Current Amplifier Gain

1.9

A/V

Error Amplifier Voltage Gain

400

730

V/V

µA/V

KHz

MHz

µA

∆I_C= ± 10µA

Error Amplifier Transconductance

Oscillator Frequency

Sync Frequency

Maximum Duty Cycle

Minimum Duty Cycle

Enable Threshold

Enable Hysteresis

Enable Pull-up Current

Under Voltage Lockout

Threshold Rising

420

0.460

460

500

1.1

Sync Drive 0.5V to 2.7V

V_FB= 1.0V

V_FB= 1.5V

3.2

2.55

2.2

2.4

2.475

220

0.7

2.5

2.6

Under Voltage Lockout

Threshold Hysteresis

Supply Current (Shutdown)

Supply Current (Quiescent)

Thermal Shutdown

200

0.95

153

µA

°C

V_EN≤ 0.4V

V_EN≥ 2.8V; V_FB= 1.5V

1.1

Note:

1) Equivalent output current = 1.5A ≥ 50% Duty Cycle

2.0A ≤ 50% Duty Cycle

Assumes ripple current = 30% of load current.

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS4155

TYPICAL PERFORMANCE CHARACTERISTICS

Light load start up

Full load start up

PWM rising edge

PWM Falling edge

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS4155

TYPICAL PERFORMANCE CHARACTERISTICS (continued)

0.5-3A transient on 5V output

Full load Sat (reference = supply at IC)

Typical waveform set at 3.3V output, 2A load and 12V input.

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS4155

PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted.

8 LEAD SOIC PLASTIC PACKAGE (S)

0.189-0.197*

(4.801-5.004)

0.123 (3.12)

0.137 (3.48)

7 6

0.228-0.244

(5.791-6.197)

0.150-0.157**

(3.810-3.988)

0.090 (2.28)

0.102 (2.59)

0.010-0.020

(0.254-0.508)

x45°

0.053-0.069

(1.346-1.752)

0.004-0.010

(0.101-0.254)

0.008-0.010

(0.203-0.254)

0°-8 ° TYP

0.014-0.019

(0.355-0.483)

0.050

(1.270)

TYP

0.016-0.050

(0.406-1.270)

S(SO- 8 ) AMS DRW# 042293

*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH

SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE

0.024(0.61)

0.063(1.60)

0.050(1.27)

**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD

FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE

0.105(2.67)

0.213(5.41)

0.138 (3.50)

RECOMMENDED LAYOUT PATTERN

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

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