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L6246
12V VOICE COIL MOTOR DRIVER
12V (±10%) OPERATION
3A MAXIMUMCURRENT CAPABILITY
0.3ΩMAXIMUM ON RESISTANCE OF EACH
POWER DMOS AT A JUNCTION TEMPERATAUREOF25°C
CLASS ABPOWER AMPLIFIERS
LOGICAND POWERSUPPLYMONITOR
POWERONRESET
PARKING FUNCTION WITH SELECTABLE
RETRACT VOLTAGE AND DYNAMIC BRAKE
BEFOREPARKING
ENABLEFUNCTION
GATE DRIVER FOR EXTERNAL BLOCKING
N-MOSFET
OVERTEMPERATUREPROTECTION
OVERTEMPERATUREWARNING OUTPUT
PQFP44PACKAGE
DESCRIPTION
The voice coil driver L6246 is a linear power amplifier designed to drive single phase bipolar DC
motors for hard disk drive applications. The device contains a selectable transconductanceloop,
which allows high precision for head positioning.
The power stage is composedof 2 power amplifiers, in AB class, with 4 DMOSs, with Rdson of
0.5Ω (Sink+Source)maximum, in a H-bridge con-
MULTIPOWER BCD TECHNOLOGY
PQFP44(10x10)
figuration. Drive voltage for the upper DMOS
FETs is provided by a charge pump circuit to ensure low Rdson.
Automaticbrake and parking of the head actuator
is performed by logic or when a failure condition
is detectedby power supply monitors.An external
resistor programs the parking voltage that enables the head retract. In addition, a 5V stable
output is provided for the external usage, and a
gate driver circuit enables an external power supply isolation N-MOSFET.
This device is built in BCD II technologyallowing
dense digital circuitry to be combined with high
power bipolar power devices and is assembled in
PQFP44.
February 1998
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L6246
PIN CONNECTION (Top view)
BLOCK DIAGRAM
C1
C2
VCP
V
CC
+12
FILTER CAP
V
DD
+5
FILTER CAP
T_CAP
RPARK
ERR_OUT
V
CC/2
ERR-
+5V REF
+5V REF_GND
N.C.
FILTER_CAP
BRAKE DELAY
-THERMAL SD
SENSE-IN+
SENSE-IN-
GND
ERR-OUT
ERR-
SENSE-OUT
N.C.
CP_GND GATE DRIVE
CHARGE
PUMP
GATE
DRIVER
+5
+
-
10K
REF1
-
10K
+
REF1
PARKING
ERROR
AMPL.
+
-
REF1
REF. VOLT.
GENERATOR
SENSE
V
CC/2
_IN+
GND
OUT-
VIN-
VIN+
-SPINDLE
START
10K
CC
V
C2
VCPC1VCCOUT+
171118 19 20 21 22
DDVCC
-AE_W_GATE
MOTOR START
MOTOR
START
V
-W_GATE
CC/2
V
30K
25K
+
GATE DRIVE
44 43 42 41 3940 38 37 36 35 34
1
2
3
4
5
6
7
8
9
10
12 13 14 15 16
VIN_OUT
4µA
-
20K
V
SENSE
AMPLIFIER
+
CC/2
VPARK
-
SENSE
_IN-
SENSE_
OUT
-POR
GND
CPGND
T_CAP
+5V REF
W_GATE
VBEMF
N.C.
33
ENABLE
32
31
-SPINDLE START
30
VCM PARK
29
-W_GATE
28
RPARK
27
VBEMF
26
+12SETPT
+5SETPT
25
24
+5V REF_GND
N.C.
23
D95IN241B
-AE
+
-
VCM
PARK
INPUT
AMPLIFIER
BRAKE
CIRCUIT
POWER AMPLIFIERS
VINVIN+
VIN_OUT
-POR
THERMAL -THERMAL SD
BRAKE DELAY
V
CC
+
-
OUT+
GND
V
CC
+
-
OUT-
GND
D95IN242B
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L6246
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
V
pow. max.
V
digital max.
V
in max.
V
in min.
I
peak
I
dc
P
tot
T
op
THERMAL DATA
Symbol Parameter Value Unit
R
th j-case
R
th j-amb
R
th j-amb
(*) Standard boardconstruction: single layer (1S 0P); size 100mm long by 100mm wide.
(**) The board constructionincludes: a 6 layer board (2S 4P,with power planes ≅80%); size 136mm longby 99mm wide; package location
near middle pointof lenght and onethird of width.
Maximum supply voltage 15 V
Maximum supply voltage 7 V
Maximum input voltage V
±0.3 V
digital
Minimum input voltage GND - 0.3 V
Peak sink/source output current 3 A
DC sink/source output current 1.7 A
Maximum total power dissipation ≅1.7 W
Operative temperature range 0 to 80 °C
Thermal resistance junction to case ≅20 °C/W
Thermalresistancejunction toambientmountedon standard PCB(*) ≅66 °C/W
Thermal resistance junction to ambient mounted on PCB (**) ≅35 °C/W
PIN FUNCTIONS
Pin Name Description
1 N.C. Not Connected.
2 Filter_cap Filter capacitor for 10V internal regulator. The capacitor is optional.
3 Brake Delay Voice Coil Motor brake delay capacitor.
4 -Thermal SD Pre Thermal Shut Down indication Output.
5 Sense_in+ Non invertingInput of Sense Amplifier.
6 Sense_in- Inverting Input of Sense Amplifier.
7 Gnd Ground.
8 Err_out Error Amplifier Output.
9 Err- InvertingInput of Error Amplifier.
10 Sense_out Output of Sense Amplifier.
11 N.C. Not Connected.
12 Vin_out Output of Input Amplifier.
13 Vin- Inverting Input of Input Amplifier.
14 Vin+ Non invertingInput of Input Amplifier.
15 +Vcc/2 Half Supply Voltage reference.
16 +Motor start Motor start Output to Spindle Controller.
17 -AE_W_Gate Write Gate Output to AE.
18 +Vdd +5V Supply.
19 +Vcc +12V Supply.
20 -POR Power On Reset. Low willsignal thefailureof thelogic supply or 12V supply
21 +5V Ref +5V Reference Output from the Voltage Reference Regulator.
22 T_cap Power On Reset Timing Capacitor. The capacitor sets the POR delay.
23 N.C. Not Connected.
24 +5V Ref Gnd Ground for VoltageReference Generator.
25 +5Setpt +5V Monitor Set Point and filtering
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L6246
PIN FUNCTIONS (continued)
Pin Name Description
26 +12Setpt +12V Monitor Set Point and filtering
27 Vbemf Input BEMF from spindle motor for parking circuit.
28 Rpark Resistor for setting the park voltage.
29 -W_Gate Write Gate Input.
30 +VCM park External input for parking. High will activate the park procedure.
31 -Spindle_start Spindle Start input.
32 +Enable Input. logic low will disable only the IC.
33 N.C. Not Connected.
34 Cpgnd Charge Pump Ground.
35 Gnd Ground.
36 Out+ Power Amplifier Output.
37 Vcc +12V Power Supply.
38 C1 Charge Pump Oscillator Output.
39 C2 Input for external Charge Pump Capacitor.
40 Vcp Output for Charge Pump Storage Capacitor.
41 Vcc +12V Power Supply.
42 Out- Power Amplifier Output.
43 Gnd Ground.
44 Gate Drive Gate Drive for External Isolation N-MOSFETS.
ELECTRICALCHARACTERISTICS (Tj=25°C,Vdd= 5V, Vcc= 12V; unless otherwise specified.)
Symbol Parameter Test Condition Min. Typ. Max. Unit
Vcc Analog/Power supply voltage
range
Vdd Digital supplyvoltage range 4.5 5 5.5 V
Idd Digital supply quiescent current Output ENABLED 5 mA
Idd Digital supply quiescent current Output DISABLED 5 mA
Icc Power supply quiescent current Output ENABLED 20 mA
Icc Power supply quiescent current Output DISABLED 10 mA
THERMAL SHUT DOWN DATA
T
h_SD
T
h_SD_H
T
h_Warn
Shut down Temperature 135 160 °C
Shut down hysteresys 25 °C
Pre Shut down alarm 115 140 °C
Pre Shut down alarm hysteresys 15 °C
EXTERNAL N-MOSFET GATE DRIVER
Vll Low level voltage 500 mV
Vhl High level voltage Vcc+4 V
Isink Current sinking capability 4 mA
Isource Current source capability 0.5 mA
POWER ON RESET AND GATE SPECIFICATION
V
dd_und_th
V
cc_und_th
POR
POR
_delay
V
dd_POR_T_R
Digital undervoltage threshold 3.8 4.1 4.45 V
Power undervoltage threshold 8.5 9.25 10.0 V
POR timeout Cpor = 1µF 375 500 625 ms
_to
Time delay forPOR Active 1
Power supply POR thereshold
Resistance
10.8 12 13.2 V
10 K
s
µ
Ω
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