8925

3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER

WITH LINEAR CURRENT CONTROL

AND POWER DMOS OUTPUTS

DISCONTINUED

PRODUCT

—

FOR

REFERENCE

ONL

Y

POWER

GROUND

7

8

9

10

11

12

13

14

15

16

17

29

30

39

38

37

36

35

34

33

32

31

POWER

GROUND

POWER

GROUND

POWER

GROUND

SUB

SUB

+

3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER

WITH LINEAR CURRENT CONTROL

AND POWER DMOS OUTPUTS

The A8925CEB is a DMOS three-phase brushless dc motor con-

troller/driver designed for use in Winchester disk drives and other data

storage applications. The power output stages are capable of

±4 A

output currents and have DMOS power outputs with less than 0.25

Ω

diodes protect the output drivers when switching inductive loads.

Thermal shutdown circuitry is provided to protect the device from ex-

cessive junction temperature.

A transconductance amplifier is used to linearly regulate the load

current and control motor speed. Internal current-sensing circuitry

eliminates the need for external sense resistors. Analog and digital

control circuitry provide complete sequencing of the output drivers as

well as providing brake, disable, and tachometer functions. A FAULT

output flag indicates the presence of an under-voltage condition on the

12 V supply, excessive junction temperature, or an invalid Hall input

combination. The A8925CEB’s commutation logic is compatible with

motors that have digital Hall-effect sensors with 120

° of electrical

separation. Internal charge pump circuitry is provided to drive the N-

channel DMOS source drivers to their required gate voltages.

The A8925CEB is provided in a 44-lead PLCC power package for

surface-mount applications. The copper batwing provides for maxi-

mum allowable package power dissipation in the smallest possible

construction.

FEATURES

s DMOS Outputs

s Low r

s Linear Current Control

s Internal Commutation Circuitry

s Internal Current Sensing

s Thermal Shutdown Circuitry

s Under Voltage Detection Circuitry

s Fault Output Flag

s Power Surface-Mount Package

Always order by complete part number: A8925CEB .

ABSOLUTE MAXIMUM RATINGS

Logic Input Voltage Range,

Package Power Dissipation,

Operating Temperature Range,

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.

Dwg. PP-034

8925