8936 Datasheet, PDF (1/10 Pages) Allegro MicroSystems – VOICE COIL MOTOR DRIVER

8936
INTERIM DATA SHEET
V_(SO_ubI_jeC_ctE_to COIL _{change without n}M_otiO_ceT₎ OR
March 16, 1993
8936 ^DRIVER
VOICE COIL MOTOR DRIVER
A8936CLW
Providing control and drive of the voice coil motor used for head
positioning in 5 V disk drive applications, the A8936C— is a full-bridge
RET REF 1
28 RET SET
driver which can be configured so that its output current is a direct
function of an externally applied control voltage or current. This linear
V _FLT 2
PROTECT
R
27 V_SENS
current control function is supplemented by additional circuitry to
V _BEMF 3
CIRCUIT
SQ
26 VEL FLT
protect the heads and the data disk during system failure or normal
GROUND 4
UV _SET 5
T R OUTP 6
OUT 7
C _{EN VEL FLT 8}
U _{INN 9}
D ^Y VEL_IN 10
L _{RETRACT 11}
WINDOW
COMP.
V _REF
+ ^VREF
–
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
O N _{FAULT 12}
MP RESET ¹³
PROTECT
CIRCUIT
R _{O SIGNAL}
SUPPLY
14
V _CC
17 H GAIN
+ ^{16 REFERENCE}
– _{15 ACT}
P _{E Dwg.PP-046A}
D _{C ABSOLUTE MAXIMUM RATINGS}
E _{N Supply Voltages, VCC and VDD ........... 6.0 V}
U _{E Output Current, IOUT (peak) .......... ±600 mA}
(continuous) ........................... ±500 mA
IN R Analog Input Voltage Range,
V_IN ................................... -0.3 V to V_CC
T ^E _{Logic Input Voltage Range,}
N ^{F VIN ............................... -0.3 V to +6.0 V}
Package Power Dissipation,
O ^{E PD ........................................ See Graph}
Operating Temperature Range,
C ^{R T}_A ^{..................................... 0°C to +70°C}
Junction Temperature, T_J .............. +150°C^†
IS R Storage Temperature Range,
T_S ................................ -55°C to +150°C
D _{FO † Fault conditions that produce excessive}
system shutdown. An under- or over-velocity sense disables the
system in a controlled sequence if a fault condition occurs.
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
external current-sense resistor. Thermal protection and under-voltage
lockout disables the system in a controlled sequence if a fault condi-
tion occurs.
FEATURES
s Over-Velocity Fault Function
s Lossless Current Sensing
s Zero Deadband
s High Transconductance Bandwidth
s User-Adjustable Transconductance Gain
s Digital Transconductance Gain Switch (4:1 Ratio)
s 5 Volt Monitor with Selectable UV Trip Point
s Retract Circuitry Functional to 0 Volts
s Chip Enable/Sleep Mode Function
s 1 V at 500 mA Output Saturation Voltage
s Internal Thermal Shutdown Circuitry
— ^{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
Always order by complete part number:
determined by system concerns and factors.
These include: system duty cycle and timing,
Part Number Package
ambient temperature, and use of any heatsinking
and/or forced cooling. For reliable operation the
specified maximum junction temperature should
A8936CJT 64-Lead Thin Quad Flatpack
not be exceeded.
A8936CLW 28-Lead SOIC
A
TM
MicroSystems, Inc.