8932-A
RET REF
V
FLT
V
BEMF
GROUND
UV
SET
R
OUT P
OUT
SWITCH
IN
N
OUT
SW
RETRACT
FAULT
MP
RESET
SIGNAL
SUPPLY
1
2
3
4
5
6
7
8
28
27
RET SET
V
SENS
V
LOAD
V
SENS FB
SGND
N
OUT
P
LOAD
SUPPLY
OUT
N
SGND
P
ACT
FB
PWR OFF
H GAIN
REFERENCE
ACT
VOICE-COIL MOTOR DRIVER
Providing control and drive of the voice-coil motor used for head
positioning in 5 V disk drive applications, the second-generation
A8932CLWA is a full-bridge driver that can be configured so that its
output current is a direct function of an externally applied control
voltage or current. This linear current control function is supplemented
by additional circuitry to protect the heads and the data disk during
system failure or normal system shutdown.
The two
±500
mA MOS driver outputs provide very low saturation
voltage and minimal power dissipation. Additional headroom is
achieved by the sense-FET structure eliminating the need for an exter-
nal current-sense resistor. Internal circuitry can be configured to
provide closed-loop velocity control of the actuator by utilizing the
generated back-EMF of the voice-coil motor. Thermal protection and
under-voltage lockout disables the system in a controlled sequence if a
fault condition occurs.
Data Sheet
26300.2A†
PROTECT
CIRCUIT
–
26
+
25
24
23
V
DD
22
21
–
9
10
11
12
13
14
+
V
REF
–
2V
+
20
19
18
17
PROTECT
CIRCUIT
+
–
16
15
V
CC
FEATURES
I
I
I
I
I
I
I
I
I
I
I
Class-B, 2
Ω
r
DS(on)
at 500 mA Output
Lossless Current Sensing
Zero Current-Loop Deadband
High Transconductance Bandwidth
User-Adjustable Transconductance Gain
Digital Transconductance Gain Switch (4:1 Ratio)
5 Volt Monitor with Selectable UV Trip Point
Retract Circuitry Functional to 0 Volts
Sleep Mode Function
Internal Back-EMF Velocity Loop Option
Internal Thermal Shutdown Circuitry
Dwg. PP-042B
ABSOLUTE MAXIMUM RATINGS
Supply Voltages, V
CC
and V
DD
............
6.0 V
Output Current, I
OUT
(peak) ...........
±600
mA
(continuous) ...........................
±500
mA
Analog Input Voltage Range,
V
IN
....................................
-0.3 V to V
CC
Logic Input Voltage Range,
V
IN
...............................
-0.3 V to +6.0 V
Package Power Dissipation,
P
D
.........................................
See Graph
Operating Temperature Range,
T
A
.....................................
0
°
C to +70
°
C
Junction Temperature, T
J
...............
+150
°
C
†
Storage Temperature Range,
T
S
................................ -55
°
C to +150
°
C
† 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.
Always order by complete part number, e.g.,
A8932CLWA
.
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
