MC3479FN Datasheet, PDF (4/10 Pages) ON Semiconductor – Stepper Motor Driver

Bias/Set
Clk
OIC
F / HS
CW / CCW
+ 12 V
0.1 mF
V_M
16
L2
2
1.0 k
56 k
1.0 k
6
3
MC3479P
7
14
8
9
15
10
4 5 12 13
L1
1.0 k
L4 1.0 k
1.0 k
L3
1.0 k
11
+ 12 V
4.0 k
Phase A
Figure 2. AC Test Circuit
MC3479
Bias/Set ^VM
Input
0
L1 − L4
Outputs
PW_BS
V_M − 1.0
V_M − 1.0
t_PBSD
(High Impedance)
t_PBSD
Note: t_r, t_f (10% to 90%) for
input signals are p 25 ns.
Figure 3. Bias/Set Timing (Refer to Figure 2)
PIN FUNCTION DESCRIPTION
Pin #
Function
Symbol
16
Power Supply
V_M
Description
Power supply pin for both the logic circuit and the motor coil current. Voltage range is
+ 7.2 to + 16.5 V.
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.
1
Clamp Diode Voltage
V_D
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 12.
2, 3,
14, 15
Driver Outputs
L1, L2 L3, High current outputs for the motor coils. L1 and L2 are connected to one coil, and L3 and
L4
L4 to the other coil.
6
Bias/Set
B/S
This pin is typically 0.7 volts below V_M. The current out of this pin (through a resistor to
ground) determines the maximum output sink current. If the pin is opened (I_BS < 5.0 mA)
the outputs assume a high impedance condition, while the internal logic presets to a
Phase A condition.
7
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.
9
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 one−half step. See Figure 7
for sequence.
10
Clockwise/
CW/CCW This input allows reversing the rotation of the motor. See Figure 7 for sequence.
Counterclockwise
8
Output Impedance
OIC This input is relevant only in the half step mode (Pin 9 > 2.0 V). When low (Logic “0”),
Control
the two driver outputs of the non−energized coil will be in a high impedance condition.
When high the same driver outputs will be at a low impedance referenced to V_M. See
Figure 7.
11
Phase A
Ph A This open−collector output indicates (when low) that the driver outputs are in the Phase
A condition (L1 = L3 = V_OHD, L2 = L4 = V_OLD).
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