Data Sheet

28210.10

UNIPOLAR STEPPER-MOTOR

TRANSLATOR/DRIVERS

Combining low-power CMOS logic with high-current, high-voltage

power FET outputs, the Series SLA7060M translator/drivers provide
complete control and drive for a two-phase unipolar stepper motor with
internal fixed off time and pulse-width modulation (PWM) control of
the output current in a power multi-chip module (PMCMTM). There are
no phase-sequence tables, high-frequency control lines, or complex
interfaces to program.

The CMOS logic section provides the sequencing logic, direction,

control, synchronous/asynchronous PWM operation, and a "sleep"
function. The minimum CLOCK input is an ideal fit for applications
where a complex µP is unavailable or overburdened. TTL or LSTTL
may require the use of appropriate pull-up resistors to ensure a proper
input-logic high. For PWM current control, the maximum output
current is determined by the user's selection of a reference voltage and
sensing resistor. The NMOS outputs are capable of sinking up to 1, 2,
or 3 A (depending on device) and withstanding 46 V in the off state.
Clamp diodes provide protection against inductive transients. Special
power-up sequencing is not required.

Half-, quarter-, eighth-, and sixteenth-step operation are externally

selectable for the SLA7060/61/62M. Half-step excitation alternates
between the one-phase and two-phase modes (AB-B-AB-A-AB-B-AB-
A), providing an eight-step sequence.

The Series SLA7060M is supplied in a 21-pin single in-line power-

tab package with leads formed for vertical mounting (suffix LF2102).
The tab is at ground potential and needs no insulation. For high-current
or high-frequency applications, external heat sinking may be required.
This device is rated for continuous operation between -20°C and
+85°C.

EATURES

To 3 A Output Rating
Internal Sequencer for Microstepping Operation
PWM Constant-Current Motor Drive
Cost-Effective, Multi-Chip Solution
100 V, Avalanche-Rated NMOS
Low r

DS(on)

NMOS Outputs

Advanced, Improved Body Diodes
Inputs Compatible with 3.3 V or 5 V Control Signals
Sleep Mode
Internal Clamp Diodes

Always order by complete part number, e.g., SLA7060MLF2102

BSOLUTE

AXIMUM

ATINGS

Driver Supply Voltage, V

................ 46 V

Load Supply Voltage, V

.................. 46 V

Output Current, I

SLA7060M ................................. 1.0 A*
SLA7061M ................................. 2.0 A*
SLA7062M ................................. 3.0 A*

Logic Supply Voltage, V

............... 7.0 V

Logic Input Voltage Range,

.......................... -0.3 V to V

+ 0.3 V

Sense Voltage, V

........................ ±2.0 V

Reference Input Voltage Range,

REF ..................................

-0.3 V to V

+ 0.3 V

Package Power Dissipation,

....................................... See Graph

Junction Temperature, T

............. +150°C

Operating Temperature Range,

................................. -20°C to +85°C

Storage Temperature Range,

............................... -30°C to +150°C

* Output current rating may be limited by duty cycle,
ambient temperature, and heat sinking. Under any set of
conditions, do not exceed the specified current rating or
junction temperature.
Internal filtering provides protection against transients
during the first 1 µs of the current-sense pulse.

SLA7060M

THRU

SLA7062M

PRELIMINARY INFORMATION

(subject to change without notice)

September 24, 2003

SLA7060M

THRU

SLA7062M

UNIPOLAR STEPPER-MOTOR

TRANSLATOR/DRIVERS

www.allegromicro.com

Electrical characteristics: unless otherwise noted at T

= +25°C, V

= 24 V, V

= 5.0 V.

Limits

Characteristic

Symbol

Test Conditions

Min.

Typ.

Max.

Units

Output drivers

Driver Supply Volt. Range

Operating

Drain-Source Breakdown

(BR)DS

= 44 V, I

= 1 mA

100

Output On Resistance

DS(on)

SLA7060M, I

= 1.0 A

700

850

SLA7061M, I

= 2.0 A

250

400

SLA7062M, I

= 3.0 A

180

240

Body Diode Forward Volt.

SLA7060M, I

= 1.0 A

0.85

1.1

SLA7061M, I

= 2.0 A

0.95

TBD

SLA7062M, I

= 3.0 A

0.95

TBD

Driver Supply Current

REF

> 2.0 V (sleep mode)

100

µA

Control logic

Logic Supply Volt. Range

Operating

3.0

5.0

5.5

Logic Input Voltage

0.75V

0.25V

Logic Input Current

±1.0

µA

CLOCK, RESET, CW/CCW, and SYNC.

±1.0

µA

M1 and M2

-25

-50

-75

µA

Max. Clock Frequency

clk

250*

kHz

PWM Off Time

off

70 to 100%I

trip

max

µs

38 to 64%I

trip

max

9.0

µs

9 to 30%I

trip

max

7.0

µs

PWM Min. On Time

on(min)

1.8

µs

Ref. Input Voltage Range

REF

Operating

1.5

Sleep mode

2.0

Ref. Input Current

REF

±10

µA

Monitor Output Voltage

MoH

- 1.25

MoL

1.25

Monitor Output Current

±3.0

Sense Voltage

Trip point at 100% I

0.95V

REF

1.05V

REF

Sense Input Current

SENSE

±10

µA

Propagation Delay Time

PLH

Clock rising edge to output on

2.0

µs

PHL

Clock rising edge to output off

1.5

µs

Logic Supply Current

4.0

Typical values are given for circuit design information only.
*Operation at a clock frequency greater than the specified minimum value is possible but not warranted.

SLA7060M

THRU

SLA7062M

UNIPOLAR STEPPER-MOTOR

TRANSLATOR/DRIVERS

www.allegromicro.com

Functional description

Device operation.

These devices are complete

microstepping motor drivers with built in translator for
easy operation with minimal control lines. They are
designed to operate unipolar stepper motors in half-,
quarter-, eighth-, and sixteenth-step modes. The current in
each of the four outputs, all n-channel DMOS, is regulated
with fixed off time pulse-width modulated (PWM) control
circuitry. The current at each step is set by the value of an
external current-sense resistor (R

), a reference voltage

REF

), and the DAC's output voltage controlled by the

output of the translator.

At V

power up, or reset, the translator sets the DACs

to the home state (see figures for reset conditions). When
a step command signal occurs on the CLOCK input the
translator automatically sequences the DACs to the next
level (see table 2 for the current level sequence). The
microstep resolution is set by inputs M1 and M2 as shown
in table 1.

RESET input.

The RESET input sets the translator to a

predefined home state (see table 2) and turns off all of the
DMOS outputs. The monitor output (MO) goes low and
all STEP inputs are ignored until the RESET input goes
low. A low-pass filter is integrated into the reset circuit;
therefore a 5 µs delay is required between the falling edge
of the RESET input and the rising edge of the CLOCK
input.

Monitor output (MO).

A logic output indicator of the

initial/home state of the translator (45°). At power up the
translator is reset to the home state (phase A and phase B
output currents are both at the half-step position or
70.7%). This output is also high at the 135°, 225°, and
315° positions.

CLOCK (step) input.

A low-to-high transition on the

clock input sequences the translator, which controls the
input to the DACs and advances the motor one increment.
The size of the increment is determined by the state of
inputs M1 and M2 (see table 1). The hold state is done by
stopping the CLOCK input regardless of the input level

Microstep select (M1 and M2).

These logic-level

inputs set the translator step mode per table 1. Changes to
these inputs do not take effect until the rising edge of the
clock input.

Direction (CW/CCW) input.

This logic-level input sets

the translator step direction. Changes to this input do not
take effect until the rising edge of the clock input.

Internal PWM current control.

Each pair of outputs is

controlled by a fixed off-time (7 to 12 µs, depending on
step) PWM current-control circuit that limits the load
current to a desired value (I

TRIP

). Initially, an output is

enabled and current flows through the motor winding and
R

. When the voltage across the current-sense resistor

equals the DAC output voltage, the current-sense compara-
tor resets the PWM latch, which turns off the driver for the
fixed off time during which the load inductance causes the
current to recirculate for the off time period. The driver is
then re-enabled and the cycle repeats.

Synchronous operation mode.

This function pre-

vents occasional motor noise during a "hold" state, which
normally results from asynchronous PWM operation of
both motor phases. A logic high at the SYNC input is
synchronous operation; a logic low is asynchronous
operation. The use of synchronous operation during
normal stepping is not recommended because it produces
less motor torque and can cause motor vibration due to
stair-case current.

Sleep mode.

Applying a voltage greater than 2 V to the

REF pin disables the outputs and puts the motor in a free
state (coast). This function is used to minimize power
consumption when not in use. Although it disables much
of the internal circuitry including the output MOSFETs
and regulator, the sequencer/translator circuit is active and
therefore a microcontroller can set the step starting point
for the next operation during the sleep mode. When
coming out of sleep mode, wait 100 µs before issuing a
step command to allow the internal circuitry to stabilize.

Table 1. Step Modes

Input

Step Mode

Half Step

Quarter Step

Eighth Step

Sixteenth Step

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000

SLA7060M

THRU

SLA7062M

UNIPOLAR STEPPER-MOTOR
TRANSLATOR/DRIVERS

Table 2. Step Sequencing

(CW/CCW = L)

Phase A or A\

Phase B or B\

Half

Quarter

Eighth

Sixteenth

Current

Step

Step #

[%I

trip

max]

[%I

trip

max]

Angle

70.7

45*

77.3

63.4

83.1

55.5

88.2

47.1

92.4

38.2

67.5

95.7

29.0

98.1

19.5

100

9.8

100

-9.8

98.1

-19.5

95.7

-29.0

92.4

-38.2

102.5

88.2

-47.1

83.1

-55.5

77.3

-63.4

70.7

-70.7

135

63.4

-77.3

55.5

-83.1

47.1

-88.2

38.2

-92.4

157.5

29.0

-95.7

19.5

-98.1

9.8

-100

180

-9.8

-100

-19.5

-98.1

-29.0

-95.7

-38.2

-92.4

202.5

-47.1

-88.2

-55.5

-83.1

-63.4

-77.3

-70.7

225

-77.3

-63.4

-83.1

-55.5

-88.2

-47.1

-92.4

-38.2

247.5

-95.7

-29.0

-98.1

-19.5

-100

-9.8

-100

270

-100

9.8

-98.1

19.5

-95.7

29.0

-92.4

38.2

292.5

-88.2

47.1

-83.1

55.5

-77.3

63.4

-70.7

70.7

315

-63.4

77.3

-55.5

83.1

-47.1

88.2

-38.2

92.4

337.5

-29.0

95.7

-19.5

98.1

-9.8

100

360

9.8

100

19.5

98.1

29.0

95.7

38.2

92.4

22.5

47.1

88.2

55.5

83.1

63.4

77.3

70.7

45*

* Home state; MO output high. MO output high.

SLA7060M

THRU

SLA7062M

UNIPOLAR STEPPER-MOTOR

TRANSLATOR/DRIVERS

www.allegromicro.com

Applications information

Layout.

The printed wirting board should use a heavy ground

plane.

For optimum electrical and thermal performance, the

driver should be soldered directly into the board.

The driver supply terminal, VBB, should be decoupled

with an electrolytic capacitor (>47 µF is recommended)
placed as close to the device as possible.

To avoid problems due to capacitive coupling of the

high dv/dt switching transients, route the high-level, output
traces away from the sensitive, low-level logic traces.
Always drive the logic inputs with a low source impedance
to increase noise immunity.

Grounding.

A star ground system located close to the

driver is recommended. The logic supply return and the
driver supply return should be connected together at only a
single point -- the star ground.

Logic supply voltage, V

Transients at this terminal

should be held to less than 0.5 V to avoid malfunctioning
operation. Both V

and V

may be turned on or off

separately.

Logic inputs.

Unused logic inputs (CW/CCW, M1, M2,

RESET, or SYNC) must be connected to either ground or
the logic supply voltage.

Current sensing.

To minimize inaccuracies caused by

ground-trace IR drops in sensing the output current level,
the current-sense resistors, R

, should have an independent

ground return to the star ground of the device. This path
should be as short as possible. For low-value sense
resistors, the IR drops in the printed wiring board sense
resistor's traces can be significant and should be taken into
account. The use of sockets should be avoided as they can
introduce variation in R

due to their contact resistance.

PWM current control.

The maximum value of current

limiting (I

TRIP

) is set by the selection of R

and the voltage

at the REF input with a transconductance function ap-
proximated by:

TRIP

= V

REF

The required V

REF

should not be less than 0.1 V. If it is,

should be increased for a proportionate increase in

REF

Typical application

RS = 0.1

to 2

R1 = 10 k

R2 = 5.1 k

R3 = 10 k

CA = 100 µF, 50 V

CB = 10 µF, 10 V

C1 = 0.1 µF

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000

SLA7060M

THRU

SLA7062M

UNIPOLAR STEPPER-MOTOR
TRANSLATOR/DRIVERS

Applications Information (cont'd)

Continuous

Discontinuous

mode

Normalized FET on resistance

Sync. signal generator

Reference voltage.

In the Typical Application shown,

resistors R

and R

set the reference voltage as:

REF

x R

)/(R

+ R

)

The trimming of R

allows for the resistor tolerances

and REF input current. The sum of R

should be less

than 50 k

to minimize the effect of I

REF

Minimum output current.

The Series SLA7060M uses

fixed off-time PWM current control. Due to internal logic
and switching delays, the actual load current peak will be
slightly higher than the calculated I

TRIP

value (especially

for low-inductance loads). These delays, plus the mini-
mum recommended V

REF

, limit the minimum value the

current-control circuitry can regulate. An application with
this device should maintain continuous PWM control in
order to obtain optimum torque out of the motor. The
boundary of the load current (I

O(min)

) between continuous

and discontinuous operation is:

O(min)

= [(V

+ V

)/R

] x [(1/e

toff/[Rm x Lm]

) - 1]

where V

= load supply voltage

= body diode forward voltage

= motor winding resistance

off

= PWM off time

= motor winding inductance

To produce zero current in a motor, the REF input

should be pulled above 2 V, turning off all drivers.

Synchronous operation mode.

If an external signal

is not available to control the synchronous operation
mode, a simple circuit can keep the SYNC input low while
the CLOCK input is active; the SYNC input will go high
(synchronous operation) when the CLOCK input stays low
("hold"). The RC time constant determines the sync
trransition timing.
NOTE The use of this function except at 0, 70.7, or

100%I

trip

max (half-step positions 0 through 8)

is not

recommended.

Temperature effects on FET outputs.

Analyzing

safe, reliable operation includes a concern for the relation-
ship of NMOS on resistance to junction temperature.
Device package power calculations must include the
increase in on resistance (producing higher on voltages)

Io=0.5A

Io=0.7A

Io=1.0A

0.2

0.4

0.6

0.8

1.2

1.4

1.6

-50

-25

100

125

150

Junction temperature in C

Vds(on) (V)

SLA7060M

THRU

SLA7062M

UNIPOLAR STEPPER-MOTOR

TRANSLATOR/DRIVERS

www.allegromicro.com

Applications Information (cont'd)

Allowable avalanche energy

Waveforms during avalanche breakdown

caused by increased operating junction temperatures. The
figure provides a normalized on-resistance curve, and all
thermal calculations should consider increases from the
given +25°C limits, which may be caused by internal
heating during normal operation.

These power MOSFET outputs feature an excellent

combination of fast switching, ruggedized device design,
low on resistance, and cost effectiveness.

Avalanche energy capability.

There is a surge voltage

expected when the output MOSFET turns off, and this
voltage may exceed the MOSFET breakdown voltage
(V

(BR)DS

). However, the MOSFETs are avalanche type

and as long as the energy (E

(AV)

), which is imposed on the

MOSFET by the surge voltage, is less than the maximum
allowable value, it is considered to be within its safe
operating area. Note that the maximum allowable ava-
lanche energy is reduced as a function of temperature.

In application, the avalanche energy (E

(AV)

) dissipated

by the MOSFET is approximated as

(AV)

= V

DS(AV)

x 0.5 x I

x t

Output circuit for avalanche energy

calculations

Lead temperature T

[°C) at GND pin (#11) close to the package

SLA7062M

SLA7061M

SLA7060M

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000

SLA7060M

THRU

SLA7062M

UNIPOLAR STEPPER-MOTOR
TRANSLATOR/DRIVERS

Terminal list

Terminal

Name

Terminal Description

1, 2

OUTA

Driver outputs for phase A

3, 4

OUTA\

Driver outputs for phase A\

SENSEA

Phase A current sense

VDD

Logic power supply, V

REF

Current set & "sleep" control

RESET

Logic control input

CW/CCW

Forward/reverse logic control input

CLOCK

Step clock input

GND

Supply negative return

Step mode logic control input

Monitor logic output

SYNC

Synchronous PWM control input

VBB

Driver power supply, V

SENSEB

Phase B current sense

18, 19

OUTB\

Driver outputs for phase B\

20, 21

OUTB

Driver outputs for phase B

The products described herein are manufactured in Japan by

Sanken Electric Co., Ltd. for sale by Allegro MicroSystems, Inc.

Sanken and Allegro reserve the right to make, from time to time,

such departures from the detail specifications as may be required to
permit improvements in the performance, reliability, or
manufacturability of its products. Therefore, the user is cautioned to
verify that the information in this publication is current before placing
any order.

When using the products described herein, the applicability and

suitability of such products for the intended purpose shall be reviewed
at the users responsibility.

Although Sanken undertakes to enhance the quality and reliability of

its products, the occurrence of failure and defect of semiconductor
products at a certain rate is inevitable.

Users of Sanken products are requested to take, at their own risk,

preventative measures including safety design of the equipment or
systems against any possible injury, death, fires or damages to society
due to device failure or malfunction.

Sanken products listed in this publication are designed and intended

for use as components in general-purpose electronic equipment or
apparatus (home appliances, office equipment, telecommunication
equipment, measuring equipment, etc.). Their use in any application
requiring radiation hardness assurance (e.g., aerospace equipment) is
not supported.

When considering the use of Sanken products in applications where

higher reliability is required (transportation equipment and its control
systems or equipment, fire- or burglar-alarm systems, various safety
devices, etc.), contact a Sanken sales representative to discuss and
obtain written confirmation of your specifications.

The use of Sanken products without the written consent of Sanken in

applications where extremely high reliability is required (aerospace
equipment, nuclear power-control stations, life-support systems, etc.) is
strictly prohibited.

The information included herein is believed to be accurate and

reliable. Application and operation examples described in this
publication are given for reference only and Sanken and Allegro
assume no responsibility for any infringement of industrial property
rights, intellectual property rights, or any other rights of Sanken or
Allegro or any third party that may result from its use.

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