SGS Thomson Microelectronics L6243D, L6243 Datasheet

12V/5V OPERATION
PARKING FUNCTION FOR HARD DISK

HEAD ACTUATOR
OUTPUT CURRENT UP TO 2A DC, 2.5A

PEAK
LOW SATURATIONVOLTAGE
LOGICAND POWERSUPPLYMONITOR
LINEARCONTROL
THERMALPROTECTION
ENABLEFUNCTION
CURRENT SENSE RESISTOR CONNEC-

TIONS

DESCRIPTION

The L6243/D is a Bipolar IC developed for use in
Hard Disk Head Actuator positioning applications.
The Power Op-Amp Output Bridge, Differential
Amplifier, and Error Amplifier, are controlled by
TTL/CMOS, input compatible, Digital Logic, and
an Analog Current Control Voltage. A simple
RC compensation network, tied to the output of
the Error Amp, will configure the system to work

L6243

L6243D

VOICE COIL MOTOR DRIVER

PLCC44 SO(24+2+2)

ORDERING NUMBERS:

L6243 L6243D

as a Transconductance Amplifier to drive a
VoiceCoil Motor in LinearMode.

Additional features include Power On Reset De­lay, Enable and Park, as well as a general pur­pose Operational Amplifier. A logic low at the
Park input activates the parking function. Holding
the Enable input low will disable the device by
forcing the outputs into a tristate mode. Power
Fail Monitors for the logic and power supplies in­itiate an automatic parking sequence during a
power failure. A resistor programmed parking
voltageenablesa constant velocityhead retract.

BLOCK DIAGRAM

July 1996

This is advanced information on a new product now in development or undergoing evaluation.Details are subjectto change without notice.

1/12

L6243-L6243D

PIN CONNECTION

PLCC-44

ERROR AMP INPUT

ERROR AMP OUTPUT

OP AMP OUTPUT

WRITE DISABLE OUTPUT

POWER ON RESET OUTPUT

PARK VOLTAGE PROGRAM

(Top view)

GND

OP AMP -INPUT

OP AMP +INPUT

GND

GND

7
8
9
10
11
12
13
14
15
16
17

GND

N.C.

N.C.

REF

V

SENSE AMP OUTPUT

123564

(12V)

CC

V

PARK POWER

OOUTPUT B

GND

N.C.

SENSE AMP INPUT B

40414244 43

39

GND

38

SENSE AMP INPUT A

37

N.C.

36

GND

35

N.C.

34

GND

33

N.C.

32

N.C.

31

GND

30

ENABLE INPUT

29

GND

SO24+2+2

POWER ON RESET OUTPUT

V

REF

N.C.
N.C.
N.C.

ERROR AMP INPUT SENSE AMP INPUT B

ERROR OUTPUT

GND
GND

WRITE DISABLE OUTPUT

PARK VOLTAGE PROGRAM

POWER FAIL THRESHOLD

VCCSENSE OUTPUT

POWER ONRESET DELAY

N.C.

POWER FAIL THRESHOLD

1
2
3
4
5
6
7
8
9
10
11
12
13
14

SENSE OUTPUT

CC

V

POWER ON REST DELAY

D96IN450

2322211918 20 28272624 25

(12V)

CC

V

LOGIC SUPPLY SENSE (5V)

N.C.

N.C.

5V FILTER

OUTPUT A

PARK INPUT

SENSE AMP OUTPUT

28

V

27

CC

PARK POWER

26

OUTPUT B

25
24

SENSE AMP INPUT A23
GND

22

GND

21

ENABLE

20

PARK INPUT

19

OUTPUT A

18

5V FILTER

17

V

16

CC

LOGIC SUPPLY SENSE (5V)

15

D96IN449

2/12

L6243-L6243D

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V
V
V

I
I

P

T

THERMAL DATA

Symbol Description L6243 L6243D Unit

R

th j-pin

R

th j-amb

R

th j-amb

Supply Voltage 18 V

S

Input Voltage 0.3V to V

IN

Differential Input Voltage ±V

ID

DC Output Current 2 A

O

Peak Output Current (non repetitive) 2.5 A

p

Total Power Dissipation (T

tot

=70°C) for L6243

amb

for L6243D

Storage and Junction Temperature -55 to +150 °C

stg

Thermal Resistance Junction to pin
Thermal Resistance Junction to pin floating in air
Thermal Resistance Junction to pin 16 cm

2

copper area on board

12
62
36

S

2

1.2

heat sink

S

14
50

W
W

°C/W
°C/W

C/W

°

PIN FUNCTIONS

Name Function

V

CC

GND Common Ground.

V

ref

ENABLE Input. Logic low will disable IC.

PARK POWER InputPower supply for the parking circuit.

CURRENT SENSE OUT Current sense operational amplifier output.

ERROR AMP IN Erroramplifier inverting input.

ERROR AMP OUT Erroramplifier output.

SENSE IN

±

OUT A, B Outputs of the two Power Operational Amplifiers Connections for Voice coil Motor.

PARK External input for parking. Low will activate the park procedure.

PARK VOLTAGE PROGRAM Inputto set the park voltage.

POWERFAIL THRESHOLD Supplymonitor threshold setting.

LOGIC SUPPLY SENSE Logic Supply Sense.

5V FILTER Capacitor connection to filter the logic supply ripple.

SENSE OUT Power supply failure monitor output.

V

CC

POR Power on reset output. Low will signal to the controller the failure of thelogic supply.

POR DELAY Capacitor connection to set the power on reset delay.

WRITE DISABLE Output for write disable. Low will disable the writing mode.

AMP– Inverting input of the additional op amp.
AMP+ Non-inverting input of the additional op amp.

AMPOUT Output of the additional op amp.

Power supply.

VoltageReference.

Inputfor external sense resistors.

3/12

L6243-L6243D

ELECTRICALCHARACTERISTICS (VS= 12V, T

=25°C;unless otherwise specified)

amb

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

S

I

d

T

j

Supply Range 4.5 13.2 V
Quiescent Drain Current 20 mA
Thermal Shutdown Junction

160 °C

Temperature

ERRORAMPLIFIER

I

b

I

OS

V

OS

Gv Large Signal Open Loop Voltage

GBW Gain Bandwidth 3 MHz

G

min

+ Output Source Current 6 mA

I

O

I

O–-

SR Slew-rate 2 V/µs

Input Bias Current 1
Input Offset Current 300 nA
Input Offset Voltage 5 mV

65 dB

Gain

Minimum Voltage Gain 5

Output Sink Current 6 mA

SENSEAMPLIFIER

RIN,V

A

d

SR Slew-rate 1 V/µs

GBW Gain Bandwidth Product 3 MHz

R

in

CMRR Common Mode Rejection Ratio 55 dB

V

ref

ref Input Impedance

9K

Differential Gain 8 V/V

Sense Input Impedance 1.5 KΩ

POWEROP. AMP.

A

µ

Ω

G

V

V

d

V

off

Voltage Gain 26 dB
Total Output Voltage Drop IO= 250mA

I

= 500mA

O

I

=1A

O

I

=2A

O

Offset Voltage on Sense

450
750

1.15

2.30

1.5

2.5

5mV

Resistor

BW Bandwidth on Resistive Load 100 KHz

GENERAL PURPOSEOP-AMP

I

b

I

OS

V

OS

G

V

GBW Gain Bandwidth Product 1 MHz

I

O+

I

O–

SR Slew Rate 1 V/µs

Input Bias Current 1 µA
Input Offset Current 300 nA
Input Offset Voltage 5 mV
Large Signal Open Loop Voltage

65 dB

Gain

Output Source Current 6 mA
Output Sink Current 6 mA

mV
mV

V
V

4/12

L6243-L6243D

ELECTRICALCHARACTERISTICS (continued)

MONITORSAND CONTROL CIRCUIT

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

V

HV
HV

V

V

V

V

V

I

prog

V

R

I

T

I

e

I

p

enl

enh

ph

pfl

ch

t1

t2

ll

f

pl

d

Threshold Voltage at Logic
Supply Sense

Threshold Voltage at Power Fail
Threshold Input

Hysteresis on V

t1

Hysteresis on Vt2 15 mV

t2

Low Level Voltage Write Disable = 2mA 250 500 mV

Enable Input Current Vi= 2.4V 100 µA

Input Current at Park Vi= 2.4V 100 µA

Equivalent Input Resistance at
5V Filter Input

Enable Low Input Voltage 0.8 V
Enable High Input Voltage 2 V
Parking Input High Voltage 2 V
Parking Input Low Voltage 0.8 V
Power Fail Low Output Voltage Il= 2mA 0.5 V
Parking Voltage Program Current 100 µA
Power On Reset Delay

Capacitor Charging
Delay Between WriteDisable

and Power on Reset Falling
Edges

t1

Power on Reset = 2mA 250 500 mV

= 0.4V –200 µA

V

i

= 0.4V –200

V

i

4.45 4.60 4.75 V

1.375 1.4 1.435 V

50 mV

6.9 KΩ

10 µA

410µs

A

µ

FUNCTIONAL DESCRIPTION

The VCM Driver is controlled via three control sig­nals, ENABLE, POWER ON RESET, and WRITE
DISABLE. An analog input voltage, ERROR AMP
IN, controls the polarity and amplitude of the VCM
driving current.

Refer to figure two. This diagram is a repre­sentation of the function of the VCM System.
Note that the signals with the bars represent the
”not true”, or ”non asserted”condition.From in­itial power up, the system is held in the Park
Mode. Upon completion of the POWER UP RE­SET DELAY the machine moves to Tristate Mode
or Run Mode, depending upon the condition of
the ENABLE input. If ENABLE is asserted, the
machine moves directly to Run Mode. If ENABLE
is not asserted, the machine moves to Tristate
Mode.

POWER ON RESET is an asynchronous output.
Additionally it affects the internal logic as a hard
wired reset and thereforeif a supplyfailure occurs
during Tristate or Run state, the machine moves
directly back to the Park Mode. A WRITE DIS­ABLE occurs a few to ten microseconds prior to
the POWER ON RESET in order for the system
to halt any read/write activity before a head re­tract begins.

While in Tristate Mode, the assertion of ENABLE
will move the machine to the Run Mode. Run
Mode will typically be the steady running state.
The deassertion of the ENABLE signal causes
the machine to move into Tristate. If it is desired
to perform an active Parking function, the PARK
input must be driven low by the external hard­ware, or the the VCM can be driven to the Park
position via the ERROR AMP IN control voltage

5/12

L6243-L6243D

FUNCTIONAL DESCRIPTION

(continued)

Function Description

input This is the Power Supply input.

V

CC

POWER FAIL

Input for the V

supplymonitor. The Thresholdcan be externally set via a voltage divider.

CC

THRESH

V

SENSE OUT

CC

Output

LOGIC SUPPLY

SENSE input

TTL compatible signal indicating the VCCsupply has dropped below the POWER FAIL
THRESHOLD.

This input is used to monitor the Five Volt Logic Supply for the external control and other support
IC’s. The LOGIC SUPPLY SENSE operates independently of the12V Power Supply. When a
5V supply failure is detected a POWER ON RESET is generated.

5V FILTER input This pin allows for the application of filter circuitry in order to avoid false triggering.

PARK POWER

input

This input is used during the Power Down/Power Fail Parking operation. When the supply goes
down, a typical Spindle Driver Circuit automatically tristates its output stages. During this time
the spindle motor spins freely and the stored energy is used to drive the VCM to the park
position. The generated BEMF is rectified and filtered across an external PARKING
CAPACITOR.

PROGRAMMABLE

Used to set the voltage applied to the VCM during an Automatic Parking Operation.

PARK VOLTAGE

input

PARK input Logic signal asserted low, activates parking.

POWER ON

RESET output

POWER ON

RESET DELAY

input

Indicates an error condition to the external control and support circuitry. A Logic Supply Fail
condition automatically initiates a POWER ON RESET. Internal 30k Pullup to LSS.

The intentof this input is to provide a time delay at power up. During this time, thePOWER ON
RESET line will be asserted (low).A POWER ON RESET, will hold the system inthe PARK
mode. Once the delay has timed out, the POWER ON RESETwill be removed to allow the
external system to assume control. When applied in a Disk Drive Application, the POWER ON
RESET DELAY will be required to have a minimum duration which will ensure that the
Read/Write Heads can be fully parked.

WRITE DISABLE

output

Becomes asserted a few microseconds prior to the assertion of POWER ON RESET.
Internal 30k Pullup to LSS.

ENABLE input This signaloriginates at the external controller and, when asserted, allows the VCM Drivers to

operate. When deasserted the VCM Driver is forced into Tristate mode. During a POWER ON
RESET condition however, the parking operation is automatic and takes priority over the
ENABLE function. Only at the end of the POWER ON RESET DELAY will the ENABLE input
become active. If active parking is desired, it will be accomplished under control of the V
signal, otherwise it is an automatic function at power down.

input The reference voltage input is basically that voltage, at which the output current is zero.

V

REF

ERROR AMP IN

input

ERROR AMP OUT

Inverting input of erroramplifier. The non inverting one is internallytied to V
Open collector output.

Error amplifier output pin.

.

ref

output

OUTPUT A power

Voice Coil poweroutput.

output

OUTPUT B power

Voice Coil poweroutput.

output

SENSE AMP IN

Sense amplifier input pins. The sense resistor is connected across these pins.

A/B signal input

SENSE AMP OUT

Output pin of sense amplifier.

signal output

AMPOUT output Output of an internal op-amp for general application.

AMP+ input General purpose op-amp non inverting input.

AMP- input General purpose op-amp inverting input.

IN

6/12

L6243-L6243D

BLOCK DESCRIPTION

OUTPUTSTAGE
It consists of two Power Op Amps connected in

bridge configuration.

CURRENT SENSEAMPLIFIER
Differential amplifier whose inputs are connected

to the sense lines and whose output is accessible
externally. Closing the loop will transform the
differentialvoltage signal from thesense lines into
a currentsignal for the Error Amplifier.

ERRORAMPLIFIER
Error amplifier which drives the output stage. The

input and the output pins are accessible exter­nally.

POWERSUPPLY MONITOROPERATION
The circuit monitorsthe logic supply voltage input

(typ 5V) and activates Power on Reset and Write
Disable output when such a supply drops below
the safeoperating limit. After the logic supply volt­age reaches its nominal value a delay capacitor
has to be charged [Tdelay=3x10e5 x C sec] be­fore Power on Reset and Write Disable outputs
change from low to high level. Falling edges of

Write Disable and Power on Reset are delayed
(typ 4µs) in order to disable the writing on thedisk
before the Power on Reset is activated. An addi­tional supervisorcircuit is present in the IC with a
programmablethreshold, which is set by an exter­nal resistive divider. The TTL compatible output
can be used separately or connected to Park in­put in orderto park the head.

The V

sense output pin can also be connected

CC

to 5V filter input in order to implement a POWER
ON RESET function sensitive both to 5V and V

CC

PARKINGCIRCUIT OPERATIONT
The voice coil driver is switched into the parking

conditionwhen Power on Resetoutput or Park in­put are low. In such a condition a fixed voltage is
superimposedon the load and the value of such a
voltage is set by connecting an external resistor
between Park Voltage Program input and
ground: (Vpark=Rext x Iref, Iref=100µA typ). Con­necting ENABLE input to GND the driver will be
disabled(outputsin high impedance mode).

THERMALSHUTDOWN
It will disable the IC when the junction tempera-

ture exceeds the threshold value above which the
devicecould be damaged.

.

Figure 1: ApplicationCircuit (The pinout refers to the L6243)

7/12

L6243-L6243D

Figure 2: Waveforms

8/12

THERMAL CHARACTERISTICS

L6243-L6243D

Figure 3: R

th (j-amb)

vs.Dissipated Power

Figure4:

R

th (j-amb)

vs. DissipatedPower

9/12

L6243-L6243D

PLCC44 PACKAGEMECHANICAL DATA

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

A 17.4 17.65 0.685 0.695
B 16.51 16.65 0.650 0.656
C 3.65 3.7 0.144 0.146

D 4.2 4.57 0.165 0.180
d1 2.59 2.74 0.102 0.108
d2 0.68 0.027

E 14.99 16 0.590 0.630

e 1.27 0.050
e3 12.7 0.500

F 0.46 0.018
F1 0.71 0.028

G 0.101 0.004
M 1.16 0.046

M1 1.14 0.045

mm inch

10/12

SO28 PACKAGEMECHANICAL DATA

L6243-L6243D

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

A 2.65 0.104
a1 0.1 0.3 0.004 0.012

b 0.35 0.49 0.014 0.019
b1 0.23 0.32 0.009 0.013

C 0.5 0.020

c1 45° (typ.)

D 17.7 18.1 0.697 0.713

E 10 10.65 0.394 0.419

e 1.27 0.050
e3 16.51 0.65

F 7.4 7.6 0.291 0.299

L 0.4 1.27 0.016 0.050

S8°(max.)

mm inch

11/12

L6243-L6243D

Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the
consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No
license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specification mentioned
in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied.
SGS-THOMSON Microelectronics products arenotauthorized foruseas criticalcomponentsin lifesupport devices or systems without express
written approval of SGS-THOMSON Microelectronics.

 1996 SGS-THOMSON Microelectronics – Printed in Italy – All Rights Reserved

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