MC3479

SEMICONDUCTOR

TECHNICAL DATA

STEPPER MOTOR

DRIVER

Order this document by MC3479/D

P SUFFIX

PLASTIC PACKAGE

CASE 648C

(Top View)

Bias/Set

Gnd

OIC

Gnd

Clk

Gnd

Bias/Set

Gnd

PIN CONNECTIONS

Full/Half
Step

CW/CCW

Phase A

CW/CCW

Full/Half Step

OIC

Clk

INPUT TRUTH TABLE

Input Low

Input High

CCW

Full Step

Half Step

Hi Z

Low Z

CW/CCW

Full/Half Step

OIC

Positive Edge Triggered

Clk

MOTOROLA ANALOG IC DEVICE DATA

Stepper Motor Driver

The MC3479 is designed to drive a twophase stepper motor in the

bipolar mode. The circuit consists of four input sections, a logic
decoding/sequencing section, two driverstages for the motor coils, and an
output to indicate the Phase A drive state.

Single Supply Operation: 7.2 to 16.5 V

350 mA/Coil Drive Capability

Clamp Diodes Provided for BackEMF Suppression

Selectable CW/CCW and Full/Half Step Operation

Selectable High/Low Output Impedance (Half Step Mode)

TTL/CMOS Compatible Inputs

Input Hysteresis: 400 mV Minimum

Phase Logic Can Be Initialized to Phase A

Phase A Output Drive State Indication (OpenCollector)

Available in Standard DIP and Surface Mount

CW/CCW

Gnd

Bias/Set

Phase A

Logic

Driver

OIC

Driver

F/H Step

Clk

Clock

Figure 1. Representative Block Diagram

OIC

Full/Half
Step

CW/CCW

ORDERING INFORMATION

Device

Operating

Temperature Range

Package

MC3479P

TA = 0

to +70

Plastic

Motorola, Inc. 1996

Rev 1

MC3479

MOTOROLA ANALOG IC DEVICE DATA

MAXIMUM RATINGS

Rating

Symbol

Value

Unit

Supply Voltage

+ 18

Vdc

Clamp Diode Cathode Voltage (Pin 1)

VM + 5.0

Vdc

Driver Output Voltage

VOD

VM + 6.0

Vdc

Drive Output Current/Coil

IOD

500

Input Voltage (Logic Controls)

Vin

0.5 to + 7.0

Vdc

Bias/Set Current

IBS

Phase A Output Voltage

VOA

+ 18

Vdc

Phase A Sink Current

IOA

Junction Temperature

+ 150

Storage Temperature Range

Tstg

65 to + 150

RECOMMENDED OPERATING CONDITIONS

Characteristic

Symbol

Min

Max

Unit

Supply Voltage

+ 7.2

+ 16.5

Vdc

Clamp Diode Cathode Voltage

VM + 4.5

Vdc

Driver Output Current (Per Coil) (Note 1)

IOD

350

Input Voltage (Logic Controls)

Vin

+ 5.5

Vdc

Bias/Set Current (Outputs Active)

IBS

300

Phase A Output Voltage

VOA

Vdc

Phase A Sink Current

IOA

8.0

Operating Ambient Temperature

+ 70

NOTE: 1. See section on Power Dissipation in Application Information.

DC ELECTRICAL CHARACTERISTICS

(Specifications apply over the recommended supply voltage and temperature range, [Notes

2, 3] unless otherwise noted.)

Characteristic

Pins

Symbol

Min

Typ

Max

Unit

INPUT LOGIC LEVELS

Threshold Voltage (LowtoHigh)

7, 8,

9 10

VTLH

2.0

Vdc

Threshold Voltage (HightoLow)

9, 10

VTHL

0.8

Vdc

Hysteresis

VHYS

0.4

Vdc

Current: (VI = 0.4 V)

Current:

(VI = 5.5 V)

Current:

(VI = 2.7 V)

IIL

100

--
--

--
--
--

+ 100

+ 20

DRIVER OUTPUT LEVELS

Output High Voltage

2, 3,

VOHD

Vdc

(IBS = 300

A): (IOD = 350 mA)

(IBS = 300

A):

(IOD = 0.1 mA)

14, 15

VM 2.0
VM 1.2

--
--

Output Low Voltage

VOLD

0.8

Vdc

(IBS = 300

A, IOD = 350 mA)

Differential Mode Output Voltage Difference (Note 4)

DVOD

0.15

Vdc

(IBS = 300

A, IOD = 350 mA)

Common Mode Output Voltage Difference (Note 5)

CVOD

0.15

Vdc

(IBS = 300

A, IOD = 0.1 mA)

Output Leakage, Hi Z State

VOD

VM, IBS = 5.0

IOZ1

100

+ 100

VOD

VM, IBS = 300

A, F/H = 2.0 V, OIC = 0.8 V)

IOZ2

100

+ 100

NOTES: 2. Algebraic convention rather than absolute values is used to designate limit values.

3. Current into a pin is designated as positive. Current out of a pin is designated as negative.
4. DVOD =

VOD1,2 VOD3,4

where: VOD1,2 = (VOHD1 VOLD2) or (VOHD2 VOLD1), and

VOD3,4 = (VOHD3 VOLD4) or (VOHD4 VOLD3).

5. CVOD =

VOHD1 VOHD2

VOHD3 VOHD4

MC3479

MOTOROLA ANALOG IC DEVICE DATA

DC ELECTRICAL CHARACTERISTICS

(Specifications apply over the recommended supply voltage and temperature range, [Notes

2, 3] unless otherwise noted.)

Characteristic

Pins

Symbol

Min

Typ

Max

Unit

CLAMP DIODES

Forward Voltage

1, 2, 3,

VDF

2.5

3.0

Vdc

(ID = 350 mA)

14, 15

Leakage Current (Per Diode)

IDR

100

(Pin 1 = 21 V; Outputs = 0 V; IBS = 0

PHASE A OUTPUT

Output Low Voltage

VOLA

0.4

Vdc

(IOA = 8.0 mA)

Off State Leakage Current

IOHA

100

(VOHA = 16.5 V)

POWER SUPPLY

Power Supply Current

(IOD = 0

A, IBS = 300

(L1 = VOHD, L2 = VOLD, L3 = VOHD, L4 = VOLD)

IMW

(L1 = VOHD, L2 = VOLD, L3 = Hi Z, L4 = Hi Z)

IMZ

(L1 = VOHD, L2 = VOLD, L3 = VOHD, L4 = VOHD)

IMN

BIAS/SET CURRENT

To Set Phase A

IBS

5.0

PACKAGE THERMAL CHARACTERISTICS

Characteristic

Symbol

Min

Typ

Max

Unit

Thermal Resistance, JunctiontoAmbient (No Heatsink)

C/W

AC SWITCHING CHARACTERISTICS

(TA = + 25

C, VM = 12 V) (See Figures 2, 3, 4)

Characteristic

Pins

Symbol

Min

Typ

Max

Unit

Clock Frequency

fCK

kHz

Clock Pulse Width (High)

PWCKH

Clock Pulse Width (Low)

PWCKL

Bias/Set Pulse Width

PWBS

Setup Time (CW/CCW and F/HS)

107

tsu

5.0

Hold Time (CW/CCW and F/HS)

107

Propagation Delay (ClktoDriver Output)

tPCD

8.0

Propagation Delay (Bias/SettoDriver Output)

tPBSD

1.0

Propagation Delay (ClktoPhase A Low)

711

tPHLA

Propagation Delay (ClktoPhase A High)

711

tPLHA

5.0

NOTES: 2. Algebraic convention rather than absolute values is used to designate limit values.

3. Current into a pin is designated as positive. Current out of a pin is designated as negative.

MC3479

MOTOROLA ANALOG IC DEVICE DATA

Phase A

+ 12 V

MC3479P

CW / CCW

F / HS

OIC

Clk

Bias/Set

56 k

10
4

12 13

1.0 k

1.0 k
1.0 k

1.0 k

4.0 k

0.1

+ 12 V

Figure 2. AC Test Circuit

Note: tr, tf (10% to 90%) for

input signals are

25 ns.

Figure 3. Bias/Set Timing

(Refer to Figure 2)

Bias/Set
Input

PWBS

VM 1.0

tPBSD

(High Impedance)

L1 L4
Outputs

PIN FUNCTION DESCRIPTION

Pin No.

20Pin

16Pin

Function

Symbol

Description

Power Supply

Power supply pin for both the logic circuit and the motor coil current.
Voltage range is + 7.2 to + 16.5 volts.

4, 5, 6, 7,

14, 15, 16, 17

4, 5,

12, 13

Ground

Gnd

Ground pins for the logic circuit and the motor coil current. The
physical configuration of the pins aids in dissipating heat from within
the IC package.

Clamp Diode
Voltage

This pin is used to protect the outputs where large voltage spikes may
occur as the motor coils are switched. Typically a diode is connected
between this pin and Pin 16. See Figure 11.

2, 3,

18, 19

2, 3,

14, 15

Driver Outputs

L1, L2
L3, L4

High current outputs for the motor coils. L1 and L2 are connected to
one coil, and L3 and L4 to the other coil.

Bias/Set

B/S

This pin is typically 0.7 volts below VM. The current out of this pin
(through a resistor to ground) determines the maximum output sink
current. If the pin is opened (IBS < 5.0

A) the outputs assume a high

impedance condition, while the internal logic presets to a Phase A
condition.

Clock

Clk

The positive edge of the clock input switches the outputs to the next
position. This input has no effect if Pin 6 is open.

Full/Half Step

F/HS

When low (Logic "0"), each clock input pulse will cause the motor to
rotate one full step. When high, each clock pulse will cause the motor
to rotate onehalf step. See Figure 7 for sequence.

Clockwise/
Counterclockwise

CW/CCW

This input allows reversing the rotation of the motor. See Figure 7 for
sequence.

Output Impedance
Control

OIC

This input is relevant only in the half step mode (Pin 9 > 2.0 V). When
low (Logic "0"), the two driver outputs of the nonenergized coil will be
in a high impedance condition. When high the same driver outputs will
be at a low impedance referenced to VM. See Figure 7.

Phase A

Ph A

This opencollector output indicates (when low) that the driver outputs
are in the Phase A condition (L1 = L3 = VOHD, L2 = L4 = VOLD).

APPLICATION INFORMATION

General

The MC3479 integrated circuit is designed to drive a

stepper positioning motor in applications such as disk drives
and robotics. The outputs can provide up to 350 mA to each
of two coils of a twophase motor. The outputs change state
with each lowtohigh transition of the clock input, with the
new output state depending on the previous state, as well as
the input conditions at the logic controls.

Outputs

The outputs (L1L4) are high current outputs (see

Figure 5), which when connected to a twophase motor,
provide two fullbridge configurations (L3 and L4 are not
shown in Figure 5). The polarities applied to the motor coils
depend on which transistor (QH or QL) of each output is on,
which in turn depends on the inputs and the decoding
circuitry.

MC3479

MOTOROLA ANALOG IC DEVICE DATA

Note: tr, tf (10% to 90%) for input

signals are

10 ns.

tPLHA

tPHLA

tsu

PWCLKL

PWCLKH

1.5 V

Phase A
Output

F/HS,
CW/CCW
Inputs

L1 L4
Outputs

tPCD

3.0 V

Clk

3.0 V

Figure 4. Clock Timing

(Refer to Figure 2)

6.0 V

1.5 V

Current

Drivers

and

Logic

Parasitic

Diodes

Motor Coil

B/S

IBS

To L3, L4

Transistors

CW / CCW

OIC

Clk

F/HS

Inputs

Logic Decoding

Circuit

Figure 5. Output Stages

The maximum sink current available at the outputs is a

function of the resistor connected between Pin 6 and ground
(see section on Bias/Set operation). Whenever the outputs
are to be in a high impedance state, both transistors (QH and
QL of Figure 5) of each output are off.

This pin allows for provision of a current path for the motor

coil current during switching, in order to suppress backEMF
voltage spikes. VD is normally connected to VM (Pin 16)
through a diode (zener or regular), a resistor, or directly. The
peaks instantaneous voltage at the outputs must not exceed
VM by more than 6.0 V. The voltage drop across the internal
clamping diodes must be included in this portion of the design
(see Figure 6). Note the parasitic diodes (Figure 5) across
each QL of each output provide for a complete circuit path for
the switched current.

Figure 6. Clamp Diode Characteristics

ID (mA)

300

100

200

1.0

2.0

3.0

V (V)

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