8932-A Datasheet, PDF (1/8 Pages) Allegro MicroSystems – VOICE-COIL MOTOR DRIVER

8932-A
RET REF 1
28 RET SET
V _FLT 2
PROTECT
–
V _BEMF 3
CIRCUIT
+
GROUND 4
UV _SET 5
R _{OUT P} ⁶
OUT 7
SWITCH 8
IN _N ⁹
OUT_SW ¹⁰
RETRACT ¹¹
–+
V _REF ^{– +}
2V
27 V_SENS
26 V _LOAD
25 V _{SENS FB}
24 SGND _N
23 OUT_P
V_DD 22
LOAD
SUPPLY
21 OUT _N
20 SGND P
19 ACT _FB
18 PWR OFF
FAULT 12
MP RESET ¹³
PROTECT
CIRCUIT
SIGNAL
SUPPLY
14
V _CC
17 H GAIN
+
16 REFERENCE
–
15 ACT
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.
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.
FEATURES
I
Class-B,
2
Ω
r
DS(on)
at
500
mA
Output
I Lossless Current Sensing
I Zero Current-Loop Deadband
I High Transconductance Bandwidth
I User-Adjustable Transconductance Gain
I Digital Transconductance Gain Switch (4:1 Ratio)
I 5 Volt Monitor with Selectable UV Trip Point
I Retract Circuitry Functional to 0 Volts
I Sleep Mode Function
I Internal Back-EMF Velocity Loop Option
I Internal Thermal Shutdown Circuitry
Always order by complete part number, e.g., A8932CLWA .