A8651 PDF даташит

Спецификация A8651 изготовлена «Allegro» и имеет функцию, называемую «Low Input Voltage Adjustable Frequency Dual Synchronous 2 A / 2 A Buck Regulator».

Детали детали

Номер произв	A8651
Описание	Low Input Voltage Adjustable Frequency Dual Synchronous 2 A / 2 A Buck Regulator
Производители	Allegro
логотип

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A8651

Low Input Voltage, Adjustable Frequency Dual Synchronous

2A / 2A Buck Regulator with Synchronization, 2x EN, and 2x NPOR

Features and Benefits

• AEC-Q100 Qualified

• Operating voltage range: 2.5 to 5.5 V

• UVLO stop threshold: 2.25 V (max)

• Dual outputs with up to 2 A output current per regulator

• Adjustable output voltage as low as 0.8 V

• Internal 80 mΩ high-side switching MOSFET

• Internal 55 mΩ low-side switching MOSFET

• Adjustable switching frequency ( fSW): 0.35 to 2.2 MHz

• Synchronizes to external clock: 1.2 × to 1.5 × fOSC

• 180° phase shift between switching regulators

• Sleep mode supply current less than 5 μA

• Soft start time externally set via the SS pin

• Pre-biased startup capable

• Externally adjustable compensation

• Stable with ceramic output capacitors

• Independent enable inputs and NPOR output pins

• Adjustable current limiting (OCP) for each regulator

• Hiccup mode short-circuit protection (HIC)

• Overvoltage and overtemperature protection

• Open-circuit and adjacent pin short-circuit tolerant

• Short-to-ground tolerant at every pin

Package: 20-pin TSSOP with exposed

thermal pad (suffix LP)

Not to scale

Description

The A8651 is an adjustable frequency, high output current,

PWM regulator that integrates a high-side, P-channel MOSFET

and a low-side, N-channel MOSFET. The A8651 incorporates

current-mode control to provide simple compensation, excellent

loop stability, and fast transient response. The A8651 utilizes

external compensation to accommodate a wide range of power

components to optimize transient response without sacrificing

stability. The A8651 regulates input voltages from 2.5 to 5.5 V,

down to output voltages as low as 0.8 V and is able to supply

up to 2 A of load current per regulator.

The A8651 features include an externally adjustable and

synchronizable switching frequency, an externally-set soft

start time to minimize inrush currents, independent EN inputs,

and independent NPOR outputs with 7.5 ms delay. The sleep

mode current of the A8651 control circuitry is less than 5 μA.

Protection features includeVIN undervoltage lockout (UVLO),

cycle-by-cycle overcurrent protection (OCP), hiccup mode

short-circuit protection (HIC), overvoltage protection (OVP),

and thermal shutdown (TSD). In addition, the A8651 provides

open-circuit, adjacent pin short-circuit, and short-to-ground

Continued on the next page…

Applications:

• GPS/Infotainment

• Automotive audio

• Home audio

• Network and telecom

SYNCin

CSYNC DSYNC

VIN

EN1

CP1

RZ1

CZ1

EN2

CP2

RZ2

CZ2

Typical Application Diagram

5 FSET/SYNC

RFSET

SW1 1

CIN1

20 VIN1

16 GND

2 PGND1

CSS1

3 EN1

17 COMP1

SS1

ISET1

RSET1

11 VIN2

A8651

FB1 18

NPOR1 15

SW2 10

CIN2

9 PGND2

FB2 14

CSS2

8 EN2

COMP2

SS2

ISET2

NPOR2 6

RSET2

LO1

RFB1

RFB2

LO2

RFB3

RFB4

VOUT1

CO1

RPU1

NPOR1

VOUT2

CO2

RPU2

NPOR2

A8651-DS

Free Datasheet http://www.Datasheet4U.com

No Preview Available !

A8651

Low Input Voltage, Adjustable Frequency Dual Synchronous

2A / 2A Buck Regulator with Synchronization, 2x EN, and 2x NPOR

Description (continued)

protection at every pin to satisfy the most demanding automotive

applications.

The A8651 device is available in a 20-pin TSSOP package with

exposed thermal pad for enhanced thermal dissipation (suffix LP).

It is lead (Pb) free, with 100% matte tin leadframe plating.

Selection Guide

Part Number

Operating Ambient

Temperature Range

TA, (°C)

A8651KLPTR-T

–40 to 125

*Contact Allegro™ for additional packing options.

Package

20-pin TSSOP with

exposed

thermal pad

Packing*

4000 pieces per

13-in. reel

Leadframe Plating

100% matte tin

Absolute Maximum Ratings1

Characteristic

Symbol

Notes

Rating

Unit

VIN1 and VIN2 to GND

SW1 and SW2 to GND2

All Other Pins

VIN

VSW

Continuous

t < 50 ns

–

–0.3 to 6.0

–0.3 to VIN + 0.3

–1.0 to VIN +2.0

–0.3 to 6.0

Operating Ambient Temperature

TA K temperature range

–40 to 125

ºC

Maximum Junction Temperature

TJ(max)

150 ºC

Storage Temperature

Tstg

–55 to 150

ºC

1Operation at levels beyond the ratings listed in this table may cause permanent damage to the device. The Absolute Maximum ratings

are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the Electrical

Characteristics table is not implied. Exposure to Absolute Maximum-rated conditions for extended periods may affect device reliability.

2SW1 and SW2 have internal clamp diodes to GND and VIN. Applications that forward bias these diodes should take care not to exceed

the A8651 package power dissipation limits.

Thermal Characteristics may require derating at maximum conditions, see application information

Characteristic

Symbol

Test Conditions*

Package Thermal Resistance

RθJA On 4-layer PCB based on JEDEC standard

*Additional thermal information available on the Allegro website.

Value Unit

32 ºC/W

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Free Datasheet http://www.Datasheet4U.com

No Preview Available !

A8651

Low Input Voltage, Adjustable Frequency Dual Synchronous

2A / 2A Buck Regulator with Synchronization, 2x EN, and 2x NPOR

Table of Contents

Specifications

Thermal Characteristics

Pin-out Diagram and Terminal List

Absolute Maximum Ratings

Top Level Functional Block Diagram

Detailed Functional Block Diagram

Pin-out Diagram and Terminal List

Electrical Characteristics

Characteristic Performance

Timing Diagram

Functional Description

Overview

Reference Voltage

Oscillator/Switching Frequency (RFSET, fOSC)

Transconductance Error Amplifier

Slope Compensation

ENX, VINX, and Sleep Mode

Synchronization (FSET/SYNC)

Power MOSFETs

Pulse Width Modulation (PWM)

Current Sense Amplifier

Soft Start (Startup) and Inrush Current Control

Pre-Biased Startup

Active Low Power-On Reset (NPORx)

Protection Features

Undervoltage Lockout (UVLO)

Thermal Shutdown (TSD)

Overvoltage Protection (OVP)

Pulse-by-Pulse Overcurrent Protection (OCP)

Design and Component Selection

Setting the Output Voltage (VOUT1, RFBx )

PWM Switching Frequency (RFSET)

Output Inductor (LO)

Output Capacitors

Input Capacitors

Soft Start and Hiccup Mode Timing (CSS1)

Compensation Components (RZ, CZ, CP)

A Generalized Tuning Procedure

Power Dissipation and Thermal Calculations

PCB Component Placement and Routing

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Free Datasheet http://www.Datasheet4U.com

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