LV8714TA
Dual Stepper Motor Driver with
Ultra-small Micro Steps
The LV8714 is a fully integrated dual bipolar/unipolar stepper motor driver with
ultra-small micro step drive capability. Alternatively, it can be used to drive four
DC motors independently. The device includes low RDS(ON) (upper + lower =
0.9Ω) type MOSFETs based quad H-bridges with gate drivers and can drive up
to 1.5A per H-bridge. Synchronous rectification control is implemented for all
H-bridges to lower power dissipation during a MOSFET switching. The device
implements constant-current control using PWM at 125 kHz (typ.) switching
frequency that enables the least noise motor drive solution. A built-in linear
regulator powers internal logic circuit directly from the motor supply voltage,
VM, thus eliminating need for any external regulator.
A proprietary internal current sensing mechanism is implemented that
eliminates up to four external current sense power resistors and improves the
system energy efficiency significantly. External VREF input signal for each
H-bridge controls the drive step size and can achieve over 256 micro step
resolution. Individual controls signals (ENAx and INx) are provided for
controlling each H-bridge channel independently with forward and reverse
direction control. To enhance energy efficiency further, the device can be put
into a power saving standby mode, when idle.
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48-pin TQFP with exposed pad
7 mm x 7 mm
MARKING DIAGRAM
XXXXXXXXXX
XXXXXXXXXX
AWLYYWWG
Features
Integrated quad H-bridges with independent controls
o Dual bipolar/unipolar stepper motor or quad DC motor drive
o Forward and reverse direction control
Low RDS(ON) (upper + lower = 0.9Ω) type MOSFETs
Proprietary internal current sensing
o Eliminates up to four external current sense power resistors
Over 256 micro step resolution with external VREF inputs
Single supply operation with a built-in internal regulator
No external component for driving internal MOSFETs
Constant-current control with 125 kHz (typ.) PWM switching frequency
Low power standby mode when idle
Synchronous rectification to reduce power dissipation
In-built system protection features such as:
o Under-voltage
o Over-current
o Over-temperature
1
XXXXX
A
WL
YY
WW
G
= Specific Device Code
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
ORDERING INFORMATION
Ordering Code:
LV8714TA-NH
Package
TQFP48 EP
(Pb-Free / Halogen Free)
Shipping (Qty / packing)
1000 / Tape & Reel
Typical Applications
Surveillance Camera
Stage light
Scanner
Printer
© Semiconductor Components Industries, LLC, 2014
November 2014- Rev. 2
1
Publication Order Number:
LV8714TA/D
LV8714TA
BLOCK DIAGRAM
Figure 1. LV8714TA Block Diagram
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2
LV8714TA
Logic
input
36
35
34
33
32
31
30
29
28
27
26
25
VM2
ENA2
IN2
VREF2
RCS2
GND
NC
RCS4
VREF4
IN4
ENA4
VM4
OUT3B
18
44
NC
NC
17
45
OUT1A
OUT3A
16
46
NC
NC
15
47
PGND1
PGND3
14
48
NC
NC
13
Logic
input
Logic
input
1.5kΩ
1
47µF
VM3
OUT1B
12
43
ENA3
19
11
OUT4B
IN3
OUT2B
Logic
input
42
10
20
VREF3
NC
9
NC
1.5kΩ
41
RCS3
21
8
OUT4A
VREG3
OUT2A
0.1µF
40
7
22
PS
NC
6
NC
5
39
RCS1
23
VREF1
PGND4
4
PGND2
IN1
38
3
24
ENA1
NC
2
NC
VM1
37
12V
M
1.5kΩ
1.5kΩ
Logic
input
APPLICATION CIRCUIT EXAMPLES
Figure 2. Two Bipolar Stepper motor Drive Using LV8714TA
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3
M
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4
Logic
input
1.5kΩ
0.1µF
NC
NC
15
47
PGND1
PGND3
14
48
NC
NC
13
Figure 3. Four Brushed DC motor Drive Using LV8714TA
RCS3
VREF3
IN3
ENA3
VM3
9
10
11
12
VREG3
7
8
PS
M
46
M
16
25
OUT3A
VM4
OUT1A
26
45
ENA4
17
27
NC
IN4
NC
28
44
VREF4
18
29
OUT3B
RCS4
OUT1B
30
43
NC
19
31
OUT4B
GND
OUT2B
6
42
32
20
RCS2
NC
RCS1
NC
5
41
33
21
VREF1
OUT2A
VREF2
OUT4A
4
40
Logic
input
1.5kΩ
22
IN1
NC
34
NC
3
39
IN2
23
35
PGND2
ENA2
PGND4
ENA1
38
36
NC
VM2
24
VM1
NC
2
1
M
37
Logic
input
47µF
12V
M
1.5kΩ
1.5kΩ
Logic
input
Logic
input
LV8714TA
LV8714TA
Figure 4. Two Unipolar Stepper motor Drive Using LV8714TA
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5
LV8714TA
PIN ASSIGNMENT
NC
37
24
NC
PGND2
38
23
PGND4
NC
39
22
NC
OUT2A
40
21
OUT4A
NC
41
20
NC
OUT2B
42
19
OUT4B
OUT1B
43
18
OUT3B
NC
44
17
NC
OUT1A
45
16
OUT3A
NC
46
15
NC
PGND1
47
14
PGND3
NC
48
13
NC
Figure 5. Pin Assignment
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6
LV8714TA
PIN FUNCTION DISCRIPTION
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
Pin Name
VM1
ENA1
IN1
VREF1
RCS1
PS
VREG3
RCS3
VREF3
IN3
ENA3
VM3
NC
PGND3
NC
OUT3A
NC
OUT3B
OUT4B
NC
OUT4A
NC
PGND4
NC
VM4
ENA4
IN4
VREF4
RCS4
NC
GND
RCS2
VREF2
IN2
ENA2
VM2
NC
PGND2
NC
OUT2A
NC
OUT2B
OUT1B
NC
OUT1A
NC
PGND1
NC
Description
Motor power supply pin for channel 1
Enable control pin of channel 1
Input control pin of channel 1
Reference voltage input pin of channel 1
Current sense resistor pin of channel 1
Power save mode selection pin
Internal 3.3V voltage regulator pin
Current sense resistor pin of channel 3
Reference voltage input pin of channel 3
Input control pin of channel 3
Enable control pin of channel 3
Motor power supply pin for channel 3
No connection
Channel 3 power ground pin
No connection
Channel 3 phase output A pin
No connection
Channel 3 phase output B pin
Channel 4 phase output B pin
No connection
Channel 4 phase output A pin
No connection
Channel 4 power ground pin
No connection
Motor power supply pin for channel 4
Enable control pin of channel 4
Input control pin of channel 4
Reference voltage input pin of channel 4
Current sense resistor pin of channel 4
No connection
Ground pin
Current sense resistor pin of channel 2
Reference voltage input pin of channel 2
Input control pin of channel 2
Enable control pin of channel 2
Motor power supply pin for channel 2
No connection
Channel 2 power ground pin
No connection
Channel 2 phase output A pin
No connection
Channel 2 phase output B pin
Channel 1 phase output B pin
No connection
Channel 1 phase output A pin
No connection
Channel 1 power ground pin
No connection
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7
LV8714TA
MAXIMUM RATINGS (Note 1)
Parameter
Symbol
Value
Motor Supply Voltage (Note 2)
VM
18
V
Logic Input Voltage (Note 3)
VIN
6
V
Output Peak Current per channel (Note 4)
IO(peak)
1.75
A
Output current per channel
IO(max)
1.5
A
Pd
4.86
W
Storage Temperature
Tstg
55 to 150
˚C
Junction Temperature
TJ
150
ºC
MSL
3
-
Allowable Power Dissipation (Note 5)
Moisture Sensitivity Level (MSL) (Note 6)
Unit
TSLD
260
ºC
Stresses exceeding those listed in the Absolute Maximum Rating table may damage the device. If any of these limits are exceeded,
device functionality should not be assumed, damage may occur and reliability may be affected.
Motor power supply pins are VM1, VM2, VM3 and VM4.
Logic input pins are PS, ENA1, IN1, ENA2, IN2, ENA3, IN3, ENA4 and IN4.
Condition for measuring the output peak current is that total time duration ≤ 10 ms (PWM duty cycle = 20%) at each channel.
Specified circuit board : 90mm 90mm 1.6mm, glass epoxy 4-layer board, with backside mounting. It has 1 oz internal power and
ground planes and 1/2 oz copper traces on top and bottom of the board. Please refer to Thermal Test Conditions of page 23.
Moisture Sensitivity Level (MSL): 3 per IPC/JEDEC standard: J-STD-020A
For information, please refer to our Soldering and Mounting Techniques Reference Manual, SOLDERRM/D
http://www.onsemi.com/pub_link/Collateral/SOLDERRM-D.PDF
Lead Temperature Soldering Pb-Free Versions (10sec or less) (Note 7)
1.
2.
3.
4.
5.
6.
7.
THERMAL CHARACTERISTICS
Parameter
Value
Unit
RθJA
25.7
ºC/W
Thermal Resistance, Junction-to-Case (Top) (Note 5)
RΨJT
6
ºC/W
Allowable power dissipation,
Pd (W)
Symbol
Thermal Resistance, Junction-to-Ambient (Note 5)
6.00
5.00
4.86
4-layer circuit board
with backside mounting
4.00
3.00
2.52
2.00
1.00
0.00
-20
0
20
40
60
80
100
Ambient temperature, TA (C)
Figure 6. Power Dissipation vs Ambient Temperature Characteristic
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8
LV8714TA
RECOMMENDED OPERATING RANGES (Note8)
Symbol
Ratings
Unit
Motor Supply Voltage Range (Note 2)
Parameter
VM
4 to 16.5
V
Logic Input Voltage Range (Note 3)
VIN
0.3 to 5.5
V
VREF
0 to 1.5
V
TA
20 to 85
ºC
VREF Input Voltage Range
Ambient Temperature
8.
Functional operation above the stresses listed in the Recommended Operating Ranges is not implied. Extended exposure to stresses
beyond the Recommended Operating Ranges limits may affect device reliability.
ELECTRICAL CHARACTERICALS
TA=25ºC, VM = 12V, VREF=0.6V unless otherwise noted. (Note 9)
Symbol
Parameter
Condition
IMstn
IM1(VM1)+IM2(VM2)+IM3(VM3)+IM4(VM4),
Standby Mode Current
PS=”L”, No load
IM
IM1(VM1)+IM2(VM2)+IM3(VM3)+IM4(VM4),
Supply Current
PS=”H”, No load
Thermal Shutdown Temperature
TSD
Guaranteed by design
Thermal hysteresis width
∆TSD
Guaranteed by design
Min
150
Typ
Max
Unit
0
1
μA
3.2
4.2
mA
180
˚C
40
˚C
Regulator
VREG3
REG3 Output Voltage
3
3.3
3.6
V
Output
Output On Resistance
Ronu
IO=1.5A, Upper side
0.6
0.85
Ω
Ronl
IO=1.5A, Lower side
0.3
0.5
Ω
Output leakage current
IOleak
VM=16.5V
10
μA
Diode forward voltage
VF
IF=1.5A
1.2
1.6
V
IINL
PS,ENA1,IN1,ENA2,IN2,ENA3,IN3,ENA4,IN4
,VIN=0.8V
PS,ENA1,IN1,ENA2,IN2,ENA3,IN3,ENA4,IN4
,VIN=3.3V
4.8
8
13.3
μA
20
33
55
μA
2.0
5.5
V
0
0.8
V
Logic Input
Logic Pin Input Current
IINH
Logic Input Voltage
High
VINH
Low
VINL
PS,ENA1,IN1,ENA2,IN2,ENA3,IN3,ENA4,IN4
PWM Current Control
VREF Pin Input Current
IREF
Current DetectionReference
Voltage
VREFdet
PWM (Chopping) Frequency
Fchop
Output current detection current
Ircs
9.
VREF1,VREF2,VREF3,VREF4
VREF=1.5V
VREF1,VREF2,VREF3,VREF4
VREF=0.6V
RCS1,RCS2,RCS3,RCS4,Io=0.5A,RSC=0V
0.5
μA
0.18
0.2
0.22
V
100
125
150
kHz
115
125
137
μA
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted.
Product performance may not be indicated by the Electrical Characteristics if operated under different conditions.
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9
LV8714TA
TYPICAL CHARACTERISTICS
3.5
0.50
3
0.40
IMstn (uA)
2.5
IM (mA)
0.30
2
1.5
0.20
1
0.10
0.5
0.00
0
2
4
6
8
0
10 12 14 16 18
2
VM (V)
4
6
12
14
16
18
VREG3 (V)
VREG3 (V)
4
3.5
3
2.5
2
1.5
1
0.5
0
2
4
6
8
10 12 14 16 18
0
5
10
VM (V)
0
OUTxA_Ronu
OUTxA_Ronl
OUTxB_Ronu
OUTxB_Ronl
0.5
Iout (A)
20
25
30
35
1
Figure 10. REG3 Output Voltage
vs REG3 Output Current
Ronu+Ronl (Ω)
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
15
IREG3 (mA)
Figure 9. REG3 Output Voltage
vs VM Voltage
Ron (Ω)
10
VM (V)
Figure 8. Supply Current
vs VM Voltage
Figure 7. Standby Mode Supply Current
vs VM Voltage
4
3.5
3
2.5
2
1.5
1
0.5
0
8
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
1.5
Figure 11. Output ON Resistance
vs Output Current (VM=12V)
-25
0
25
50
75
100
Temperature (˚C)
Figure 12. Output ON Resistance
vs Temperature (VM=12V)
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10
125
LV8714TA
TYPICAL CHARACTERISTICS
1.2
70
1
60
50
VF (V)
IIN (uA)
0.8
0.6
0.4
30
20
VFu
0.2
40
10
VFl
0
0
0
0.5
1
0
1.5
1
2
Iout (A)
4
5
6
Figure 14. PS Pin Input Current
vs PS Pin Input Voltage
Figure 13. Diode Forward Voltage
vs Output Current
60
60
50
ENA1
ENA2
ENA3
ENA4
50
40
IIN (uA)
IIN (uA)
3
VIN (V)
30
IN1
IN2
IN3
IN4
40
30
20
20
10
10
0
0
0
1
2
3
4
5
6
0
1
2
3
4
5
VIN (V)
VIN (V)
Figure 15. ENA1-4 Pin Input Current
vs ENA1-4 Input Voltage
Figure 16. IN1-4 Pin Input Current
vs IN1-4 Input Voltage
2.0
1.5
1.5
VINH
VINL
VIN (V)
VIN (V)
2.0
1.0
6
1.0
0.5
ENA1_VINH
ENA3_VINH
ENA1_VINL
ENA3_VINL
0.5
VINH
VINL
0.0
0.0
4
6
8
10
12
14
16
18
VM (V)
4
6
8
ENA2_VINH
ENA4_VINH
ENA2_VINL
ENA4_VINL
10
12
14
16
VM (V)
Figure 17. PS Pin H/L-level Input Voltage
vs VM Voltage
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11
Figure 18. ENA1-4 H/L-Level Input
Voltage vs VM Voltage
18
LV8714TA
TYPICAL CHARACTERISTICS
0
-2
-4
-6
-8
-10
-12
-14
-16
-18
2.0
VINH
1.5
1.0
IN1_VINH
IN3_VINH
IN1_VINL
IN3_VINL
0.5
0.0
4
6
8
IN2_VINH
IN4_VINH
IN2_VINL
IN4_VINL
10
12
14
16
VREF2
VREF3
VREF4
IREF (nA)
VIN (V)
VINL
VREF1
0
18
0.5
1
VM (V)
2
Figure 20. VREFx Pin Input Current
vs VREF Voltage
Figure 19. IN1-4 H/L-Level Input Voltage
vs VM Voltage
120
500
118
Ircs (uA)
PWM (Chopping) FRQ (kHz)
1.5
VREF1-4 (V)
116
114
112
OUT1A
OUT1B
400
OUT2A
OUT2B
OUT3A
OUT3B
300
OUT4A
OUT4B
200
100
110
0
3
8
13
18
0
0.5
1
VM (V)
Iout (A)
Figure 21. PWM (Chopping) FRQ vs VM
Voltage
Figure 22. Output detection Current
vs Iout (RCS=0V)
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12
1.5
LV8714TA
FUNCTIONAL DESCRIPTION
Power Supply Pins (VM1, VM2, VM3 AND VM4)
The LV8714 has four power supply pins, VM1, VM2,
VM3, and VM4, connected internally. Hence, it is must
that all power supply pins are connected to the same
power supply rail externally. VM1 also supplies power
to internal circuits through an internal voltage regulator.
VREG3
ENAx
INx
It is highly recommended to provide a decoupling
capacitor of 47µF close to the VM1 pin.
Internal Regulator (VM-3.3V)
An VM-3.3V regulator is integrated in the LV8714.
This regulator provides required biasing for upper
MOSFETs of each channel.
Power Save Mode Selection Pin (PS)
When the LV8714 is idle, to save power, it can be put to
a power saving, Standby mode by applying logic low to
the PS pin. While in the Standby mode, all internal
circuits of the LV8714 including voltage regulators are
put into inactive state. Table 1 shows mode selection of
the LV8714 using the PS pin
Logic Input at PS Pin
Low or Open
High
Mode
Standby
Operating
Internal Circuits
Inactive
Active
Table 1: LV8714 mode selection using the PS pin
Figure 23 shows an equivalent internal circuit of the PS
pin input.
VM1
100KΩ
Internal 3.3V Voltage Regulator Pin (VREG3)
An internal 3.3V voltage regulator acts a power source
for internal logic, oscillator, and protection circuits.
Output of this regulator is connected to the VREG3 pin.
Do not use the VREG3 pin to drive any external load. It
is recommended to connect a 0.1µF decoupling
capacitor to the VREG3 pin.
2.9KΩ
GND
Figure 24. Equivalent circuit of ENAx, INx
Motor Drive Output Pins (OUTxx)
The LV8714 has quad built-in H-bridges for driving
stepper or DC motors. Each H-bridge (channel) is made
up of upper side P-MOSFETs and lower side
N-MOSFETs. Output of each channel is connected to
OUTxA or OUTxB pins. When a channel is configured
to drive a stepper motor in forward direction, OUTxA
becomes high output and in reverse direction, OUTxB
becomes high output.
Reference Voltage Input Pins (VREFx)
Step size of a stepper motor drive is controlled by
providing a reference voltage signal at VREFx pin for
each channel. Resolution of the VREFx input enables
ultra-small micro step drive of a stepper motor in
combination with the INx input. The coil current is
proportional to the analog voltage amplitude at the
VREFx pin.
Figure 25 shows an equivalent circuit of VREFx input
pins.
500KΩ
VREG3
37KΩ
PS
VREFx
63KΩ
2.9KΩ
GND
GND
Figure 23. Equivalent circuit of the PS pin
Channel Control Pins (ENAx, INx)
Each channel of the LV8714 is controlled independently
by corresponding ENAx and INx pins. Figure 24 shows
an equivalent internal circuit of these input pins.
Figure 25. Equivalent circuit of VREF1-4
Current Sense Resistor Pins (RCSx)
The LV8714 implements a proprietary current sense
mechanism for each channel and doesn’t require any
external current sense power resistor, thus providing
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13
LV8714TA
loss-less current control that improves the energy
efficiency of the system.
To control a coil current, the individual RCSx pin is
provided for each channel. A resistor connected at this
RCSx pin decides the coil current. The coil current is
sensed internally and fed back to RCS pin with the ratio
of 1/4000. And, the output duty cycle adjusted such that
the RCSx voltage level is equal to 1/3 of the VREFx pin
voltage. Figure 26 shows the equivalent circuit of
current control.
Figure 26. Equivalent circuit of current control
Equation 1 is utilized to calculate the coil current, IOUT.
4000
∙
3
………… 1
Where,
IOUT = Coil current [A]
RCS = Resistance between RCSx and GND [Ω]
VREF = Input voltage at the VREFx pin [V]
For example, in case of
1k
0.6
The coil current is
4000 0.6
3 1000
0.8
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14
LV8714TA
DETAILED DESCRIPTION
Stepper Motor Direction Control
The stepper motor rotation direction is determined by
phase lead/lag relation between INx inputs of the
LV8714 as shown in Table 2 and Table 3.
Phase
ENA1,
Direction
ENA2 0-90 90-180 180-270 270-360
IN1
H
L
L
H
H
Forward
IN2
H
H
L
L
H
IN1
H
H
L
L
H
Reverse
IN2
H
L
L
H
H
Table 2: Stepper Motor Direction control by IN1 and
IN2
INx
Phase
ENA3,
Direction
ENA4 0-90 90-180 180-270 270-360
IN3
H
L
L
H
H
Forward
IN4
H
H
L
L
H
IN3
H
H
L
L
H
Reverse
IN4
H
L
L
H
H
Table 3: Stepper Motor Direction control by IN3 and
IN4
INx
DC Motor Direction Control
The LV8714 utilizes ENAx and INx to control the DC
motor rotation direction as shown in Table 4.
Input signal
Output
ENAx
INx
OUTxA OUTxB
L
–
Off
Off
H
L
High
Low
H
H
Low
High
X represents a channel number
Direction
Forward
Reverse
Table 4: DC Motor Direction Control by ENAx and
INx
Stepper Motor Coil Current Control
Stepper motor coil current is controlled in proportional
to VREFx and RCSx as shown in equation 1 previously.
Two phase outputs (A and B) for each stepper motor are
controlled by combination of INx and VREFx inputs as
shown in Table 5.
Input
Output (coil current)
INx VREFx ENAx
Amplitude
Polarity
Low Analog High Proportional to VREFx
A to B
High Analog High Proportional to VREFx
B to A
Table 5: Stepper Motor Coil Current Control
Figure 27 and 28 show example waveforms of output
current with in response to VREFx, ENAx and Inx
input.
Figure 27. Example waveforms for full step (forward) control
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15
LV8714TA
Figure 28. Example waveforms for 1/256 step (forward) control
PWM Constant-Current Control
The LV8714 implements constant-current control drive
by applying PWM switching to the output pin.
When the coil current becomes equal to the set target
value (as determined by equation 1), the constant
current control mechanism gets activated and performs
a repetitive sequence of Charge Slow Decay Fast
Decay (fixed 2µs) Charge… as shown in Figure 29.
The period for each sequence is fixed at 8µs(typ.).
Figure 29 shows timing chart of PWM based
constant-current control.
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16
LV8714TA
Set current
Coil current
OUT1A
OUT1B
8us
PWM cycle
1us
BLANKING Time
2us
Current control
mode
SLOW Decay
CHARGE
FAST Decay
Figure 29. Timing chart of PWM based constant-current
Three Modes of Constant-Current Control
Each PWM cycle of constant-current control is made up
of three distinct intervals – Charge, Slow Decay and
Fast Decay.
Example: Current direction A to B
Charge:
Voltage is applied to the coil until the coil current
becomes equal to the target (A = High, B = Low).
Slow Decay:
Output A and B are shorted internally resulting in
circular current (A = Low, B = Low).
Fast Decay:
Inverted bias is applied to discharge the coil current (A
= Low, B = High) that results in decreases of the coil
current.
These intervals (Charge, Slow Decay and Fast Decay)
are results of MOSFET switching as shown in Figure
30.
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LV8714TA
Switch from Charge to Slow Decay
Charge increases current
Switch from Slow Decay to Fast Decay
Current regeneration by Fast Decay
Current regeneration by Slow Decay
Switch from Fast Decay to Charge
Figure 30. MOSFET switching sequence for constant-current control
Whenever, there is a switch from the upper MOSFET to
the lower MOSFET of the same leg, the fixed dead time
of 0.375µs is provided to avoid turning on both
MOSFETs on at the same time. During this time, the
coil current flows through the body diode of the
MOSFET as seen in (2), (4) and (6) events in figure 30.
Table 6 and Table 7 show status of MOSFETs during
various intervals in a PWM cycle for different current
polarities.
OUTxA→OUTxB
Output
Tr
U1
U2
L1
L2
CHARGE
ON
OFF
OFF
ON
SLOW
Decay
OFF
OFF
ON
ON
FAST
Decay
OFF
ON
ON
OFF
OUTxB→OUTxA
Output
Tr
U1
U2
L1
L2
CHARGE
OFF
ON
ON
OFF
SLOW
Decay
OFF
OFF
ON
ON
FAST
Decay
ON
OFF
OFF
ON
Table 7: MOSFET Switching Sequence for
OUTxBOUTxA polarity
Figure 31 shows example waveforms of the stepper
motor with 1/16 step and constant-current control.
Figure 32 shows example waveforms of three events –
Charge, Slow Decay and Fast Decay.
Table 6: MOSFET Switching Sequence for
OUTxAOUTxB polarity
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LV8714TA
1/16 step
IN2
5V/div
1
IN2
VM=12V
VREF1/2=0.23V
(Iout≈0.2A)
RCS1/2=1.5kΩ
IN1=IN2≈ 125Hz
Rcoil=15Ω
IN1
5V/div
2
IN1
OUT1A
Motor Current
0.2A/div
4
2ms/div
IN2
5V/div
IN2
OUT1A
10V/div
2
OUT1B
10V/div
3
OUT1A
Motor Current
0.2A/div
4
2ms/div
1 IN2
8s(typ)
IN2
5V/div
OUT1A
10V/div
2
1 IN2
8(typ)
OUT1A
10V/div
2
OUT1B
10V/div
OUT1B
10V/div
Setting Current
OUT1A
Motor Current
0.2A/div
4
3
5s/div
3
OUT1A
Motor Current
0.2A/div
4
Setting Current
5s/div
Constant current control is synchronized to the internal PWM period 8s (typ).
Figure 31. PWM based constant-current control waveforms of the stepper motor with 1/16 step
VM=12V
VREF1/2=0.11V
(Iout≈0.1A)
RCS1/2=1.5kΩ
IN1=IN2=100Hz
Rcoil=15Ω
OUT1A
Output Voltage
10V/div
2
Setting Current
4
CHARGE
FAST Decay
OUT1A
Motor Current
0.1A/div
OUT1B
Output Voltage
10V/div
2s
3
2s/div
IN2
5V/div
SLOW Decay
Figure 32. One full PWM cycle of the constant-current control
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LV8714TA
Power-on Reset (POR) Sequence
At startup, when VM1 ≥ 4V and PS = High, it takes
50µs for the internal 3.3V regulator to provide stable
output. After the 3.3V regulator is in the active state,
ENAx needs to be pulled high to enable respective
channel output. It is recommended that VREFx input is
never floating and the required input signal is applied at
least 10µs before ENAx is pulled high. Figure 33 shows
POR and fault handling sequence.
Blanking Time
As the LV8714 switches from Fast Decay to Charge,
switching noise can lead to wrong reading by the
comparator that is comparing the coil current against the
target current. To filter out this switching noise, a fixed
1µs blanking time is provided at the beginning of the
Charge interval.
During this blanking time, the comparator ignores the
coil current reading and thus avoid false switching to the
Slow Decay interval, if the comparator detects the coil
current higher than the target current.
POR and Fault Handling Operation Flow
Low Voltage Shutdown
Over Current Protection
Thermal Shutdown
COLD START
OCP DETECTED
TSD DETECTED
SUPPLY VM1
SHUTDOWN
OUTPUT
SHUTDOWN
OUTPUT
N
PS HIGH?
PS HIGH?
Y
PS HIGH?
Y
N
ENABLE INTERNAL
VOLTAGE
REGULATOR REG3
(*1)
N
DISABLE INTERNAL
VOLTAGE
REGULATOR REG3
(*3)
Y
TJ 3V?
Y
N
ENAx HIGH?
(*2)
(*1) It takes 50µs to settle to the target voltage.
(*2) VREFx and INx input must be applied for 10µs before ENA = HIGH
(*3) Minimum 10µs of PS=LOW duration is required.
(*4) TSD detection criterion is 180°C with 40°C hysteresis
Y
DRIVER ACTIVE
Figure 33. POR and fault handling sequence
System Protection Functions
The LV8714 has built-in protection functions such as
over-current (OCP), over-temperature (Thermal
shutdown, TSD), and under-voltage (Low-voltage
shutdown, LVS) protections. These integrated
Priority
1
2
3
protections make the LV8714 based system solution
highly reliable without need for any external protection
circuit. Table 8 shows summary of LV8714 protection
functions with recovery mechanisms.
Fault Event
Condition
OUTxx Logic Regulator
Recovery
Low Voltage
LVS VREG3 2.6V
OFF
Reset
< 2.6V VM1 ≥ 4.0V
Shutdown
Thermal
Auto-recover when TJ ≤
TSD Junction temperature > 180°C
OFF
Active
ON
140ºC
Shutdown
Toggle PS input
Over-current
Upper side FET current > 2.6A
OCP
OFF
Active
ON
Protection
Lower side FET current > 2.0A
High Low (≥10s) High
Table 8: Summary of LV8714 protection functions with recovery mechanisms
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LV8714TA
Low Voltage Shutdown (LVS)
The integrated LVS protection enables safe shutdown of
the system when the VM1 drops. The VREG3 voltage is
monitored and the LVS is activated when the VREG3
voltage drops below 2.6V (typ.). It turns off output
FETs and logic circuits are put into the reset state. The
LV8714 recovers from the LVS automatically when
VM1 ≥ 4V.
Thermal Shutdown (TSD)
The built-in TSD protection prevents damage to the
LV8714 from excessive heat. To avoid false trigger, the
TSD protection is activated when the die TJ exceeds
180ºC. Once activated, it shuts down output FETs while
keeping the rest of circuit in the active state. When TJ
H-bridge
Output state
falls below 140ºC, the output stage is reactivated under
control of input signals INx, and ENAx.
Over-current Protection (OCP)
The on-chip OCP protection of the LV8714 triggers
when current above the threshold is detected internally.
Once detected for 2µs, output FETs are turned off and
the internal timer is triggered to count 128µs (typ.) of
the timer latch period. At the end of the timer latch
period, output FETs are turned on again 2µs. If during
this time, over-current is detected again, then the fault is
latched and FETs are turned off. FETs can now be
turned on again only when over-current condition is
removed and the PS pin is toggled (High -> Low (≥
10µs) -> High). Timing chart of the OCP is as shown in
Figure 34.
Output ON
Output ON
Output OFF
Over-current
Detected
Fault
detection
Release
2µs
Output OFF
Timer latch period
(typ:128µs)
Over-current
Detected
2µs
Over-current
Detected
Internal
counter
1st counter 1st counter 1st counter 1st counter
start
stop
start
stop
2nd counter
start
Figure 34. Timing Chart of OCP
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21
2nd counter
stop
LV8714TA
Example of Over-current Detection:
Short to Power
Short to GND
Load short
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22
LV8714TA
PCB GUIDELINES
VM and Ground Routing
Make sure to short-circuit VM1, VM2, VM3 and VM4
externally by a low impedance route on one side of PCB.
As high current flows into PGND, connect it to GND
through a low impedance route.
Exposed Pad
The exposed pad is connected to the frame of the
LV8714. Therefore, do not connect it to anywhere else
other than ground. If GND and PGND are in the same
plane, connect the exposed pad to the ground plane. Else,
if GND and PGND are separated, connect the exposed
pad to GND.
NC Pin Utilization
NC pins are not connected internally inside the LV8714.
If the power track that is connected to VM, outputs and
GND is wide, the power track can be connected to NC
pins.
Thermal Test Conditions
Size: 90mm × 90mm × 1.6mm (four layer PCB)
Material: Glass epoxy
Copper wiring density: L1 = 80% / L4 = 85%
Second layer is VM power supply layer.
Third layer is GND layer
L1 : Copper wiring pattern diagram (top)
L4 : Copper wiring pattern diagram (bottom)
Figure 35. Pattern Diagram of Top and Bottom Layer
Recommendation
The thermal data provided is for the thermal test
condition where 90% or more of the exposed die pad is
soldered.
It is recommended to derate critical rating parameters
for a safe design. Electrical parameters that are
recommended to be derated are operating voltage,
operating current, junction temperature, and device
power dissipation. The recommended derating for a safe
design is as shown below:
Maximum 80% or less for operating current
Maximum 80% or less for junction temperature
Check solder joints and verify reliability of solder joints
for critical areas such as exposed die pad, power pins
and grounds.
Any void or deterioration, if observed, in solder joint of
these critical areas parts, may cause deterioration in
thermal conduction and that may lead to thermal
destruction of the device.
Maximum 80% or less for operating voltage
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LV8714TA
PACKAGE DIMENSIONS
TQFP48 EP 7x7, 0.5P
CASE 932F
ISSUE C
4X 12 TIPS
NOTES:
1. DIMENSIONS AND TOLERANCING PER ASME Y14.5M, 1994.
2. CONTROLLING DIMENSION: MILLIMETERS.
3. DIMENSION b DOES NOT INCLUDE DAMBAR PROTRUSION. DAMBAR
PROTRUSION SHALL BE 0.08 MAX. AT MMC. DAMBAR CANNOT BE
LOCATED ON THE LOWER RADIUS OF THE FOOT. MINIMUM SPACE
BETWEEN PROTRUSION AND ADJACENT LEAD IS 0.07.
0.20 C A-B D
NOTE 9
D
NOTE 7
D
25
SIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE
BURRS SHALL NOT EXCEED 0.25 PER SIDE. DIMENSIONS D1 AND E1
ARE MAXIMUM PLASTIC BODY SIZE INCLUDING MOLD MISMATCH.
5. THE TOP PACKAGE BODY SIZE MAY BE SMALLER THAN THE BOTTOM
PACKAGE SIZE BY AS MUCH AS 0.15.
6. DATUMS A-B AND D ARE DETERMINED AT DATUM PLANE H.
7. A1 IS DEFINED AS THE VERTICAL DISTANCE FROM THE SEATING
37
NOTE 7
NOTE 7
A
NOTES
4&6
B
NOTE 9
E1
E
8. DIMENSIONS D AND E TO BE DETERMINED AT DATUM PLANE C.
13
48
1
D1
4X
NOTES 4 & 6
0.20 H A-B D
TOP VIEW
DETAIL A
0.08 C
A
H
0.05
L2
A2
A1
e
48X
SIDE VIEW
SEATING
PLANE
C
b
0.20 C A-B D
DETAIL A
M
L
DIM
A
A1
A2
b
D
D1
D2
E
E1
E2
e
L
L2
M
MILLIMETERS
MIN
MAX
0.95
1.25
0.05
0.15
0.90
1.20
0.17
0.27
9.00 BSC
7.00 BSC
4.90
5.10
9.00 BSC
7.00 BSC
4.90
5.10
0.50 BSC
0.45
0.75
0.25 BSC
0°
7°
RECOMMENDED
SOLDERING FOOTPRINT*
NOTE 3
D2
9.36
48X
1.13
5.30
E2
9.36
5.30
1
BOTTOM VIEW
0.50
PITCH
48X
0.29
DIMENSIONS: MILLIMETERS
*For additional information on our Pb-Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
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LV8714TA
ON Semiconductor and the ON logo are registered trademarks of Semiconductor Components Industries, LLC (SCILLC) or its subsidiaries in the United States
and/or other countries. SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of
SCILLC’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent-Marking.pdf . SCILLC reserves the right to make changes without
further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose,
nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including
without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can
and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each
customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are
not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or
sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should
Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers,
employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of,
directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was
negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all
applicable copyright laws and is not for resale in any manner.
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