a8905clb Allegro MicroSystems, Inc., a8905clb Datasheet

a8905clb

Manufacturer Part Number

a8905clb

Description

3-phase Brushless Dc Motor Controller/driver With Back-emf Sensing

Manufacturer

Allegro MicroSystems, Inc.

Datasheet

1.A8905CLB.pdf (12 pages)

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Load Supply Voltage, V

Output Current, I

Logic Supply Voltage, V

Logic Input Voltage Range,

Package Power Dissipation,

Operating Temperature Range,

Junction Temperature, T

Storage Temperature Range,

† Fault conditions that produce excessive

junction temperature will activate device thermal

shutdown circuitry. These conditions can be

tolerated, but should be avoided.

Output current rating may be restricted to a value

determined by system concerns and factors.

These include: system duty cycle and timing,

ambient temperature, and use of any heatsinking

and/or forced cooling. For reliable operation, the

specified maximum junction temperature should

not be exceeded.

CENTERTAP

GROUND

SUPPLY

BRAKE

OUT C

OUT B

OUT A

C RES

C WD

LOAD

C D2

. . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . 0 C to +70 C

. . . . . . . . . . . . -55 C to +150 C

. . . . . . . -0.3 V to V

CONTROLLER/DRIVER WITH BACK-EMF SENSING

CHARGE

BOOST

PUMP

OUT

COMMUTATION

DELAY

. . . . . . . .

MUX

FLL

. . . +150 C†

. . . . . . 14 V

. . . . 6.0 V

See Graph

C D1

CLOCK

CHIP SELECT

RESET

LOGIC

SUPPLY

FILTER

DATA IN

GROUND

DATA OUT

OSCILLATOR

INDEX

+ 0.3 V

1.25 A

Dwg. PP-040-1

8905

driver for use with CD-ROM or DVD drives. The three half-bridge

outputs are low on-resistance n-channel DMOS devices capable of

driving up to 1.25 A. The A8905CLB provides complete, reliable,

self-contained back-EMF sensing motor startup and running algorithms.

A programmable digital frequency-locked loop speed control circuit

together with the linear current control circuitry provides precise motor

speed regulation.

of operation, such as the speed control parameters, startup current limit,

sleep mode, diagnostic modes, and others.

Always order by complete part number, e.g., A8905CLB .

3-PHASE BRUSHLESS DC MOTOR

CD-ROMs

DVDs

DMOS Outputs

Low r

Startup Commutation Circuitry

Back-EMF Commutation Circuitry

Serial Port Interface

Frequency-Locked Loop Speed Control

Tachometer Signal Input

Programmable Start-Up Current

Diagnostics Mode

Sleep Mode

Linear Current Control

Internal Current Sensing

Dynamic Braking Through Serial Port

Power-Down Dynamic Braking

System Diagnostics Data Out

Data Out Ported in Real Time

Internal Thermal Shutdown Circuitry

The A8905CLB isw a three-phase brushless dc motor controller/

A serial port allows the user to program various features and modes

DS(on)

Related parts for a8905clb

a8905clb Summary of contents

Page 1

... The A8905CLB isw a three-phase brushless dc motor controller/ driver for use with CD-ROM or DVD drives. The three half-bridge outputs are low on-resistance n-channel DMOS devices capable of driving up to 1.25 A. The A8905CLB provides complete, reliable, self-contained back-EMF sensing motor startup and running algorithms. A programmable digital frequency-locked loop speed control circuit together with the linear current control circuitry provides precise motor speed regulation ...

Page 2

... CHARGE PUMP MUX TSD FILTER C/W JT 125 150 Dwg. GP-019B 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright © 1998 Allegro MicroSystems, Inc. C RES 11 12 BOOST CHARGE PUMP LOAD 1 SUPPLY OUT A 8 OUT B 9 OUT C ...

Page 3

BRUSHLESS DC MOTOR CONTROLLER/DRIVER 8905 Continued next page … ...

Page 4

BRUSHLESS DC MOTOR CONTROLLER/DRIVER CHIP SELECT CLOCK DATA A. Minimum CHIP SELECT setup time before CLOCK rising edge ...... 100 ns B. Minimum CHIP SELECT hold time after CLOCK rising edge ........... 150 ns C. Minimum DATA setup ...

Page 5

BRUSHLESS DC MOTOR CONTROLLER/DRIVER 8905 ...

Page 6

... EMF rectification in power-down conditions. Back-EMF Sensing Motor Startup and Running Algorithm. The A8905CLB provides a complete self-contained back-EMF sensing startup and running commutation scheme. The three half- bridge outputs are controlled by a state machine. ...

Page 7

Adaptive Commutation Delay. The adaptive commutation delay circuit uses the back-EMF zero-crossing indicator signal (FCOM) to determine an optimal commutation time for efficient synchronous operation. This circuit commutates the outputs, delayed from the last zero crossing, using two external timing ...

Page 8

... Current Control. The A8905CLB provides linear current control via the FILTER terminal, an analog voltage input. Maximum current limit is also provided, and is controlled in four steps via the serial port. Output current is ...

Page 9

... The Current Control Block Diagram illustrates the YANK signal and its effects. Braking. A dynamic braking feature of the A8905CLB shorts the three motor windings to ground. This is accomplished by turning the three source drivers OFF and the three sink drivers ON. Activation of the brake can be implemented through the BRAKE input or through the D2 bit in the serial port ...

Page 10

BRUSHLESS DC MOTOR CONTROLLER/DRIVER D0- Sleep/Run Mode; LOW = Sleep, HIGH = Run This bit allows the device to be powered down when not in use. D1- Step Mode; LOW = Normal Operation, HIGH = Step Only When ...

Page 11

NOTES: 1. Webbed lead frame. Leads 6, 7, 18, and 19 are internally one piece. 2. Lead spacing tolerance is non-cumulative. 3. Exact body and lead configuration at ...

Page 12

... BRUSHLESS DC MOTOR CONTROLLER/DRIVER Allegro MicroSystems, Inc. reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the design of its products. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use ...

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