ON LV8727 Pwm current control stepping motor driver Datasheet

Ordering number : ENA1998
LV8727
Bi-CMOS LSI
PWM Current Control
Stepping Motor Driver
http://onsemi.com
Overview
The LV8727 is a PWM current-controlled micro step bipolar stepping motor driver. This driver can do eight ways of
micro step resolution of Half, 1/8, 1/16, 1/32, 1/64, 1/128, 1/10, 1/20 Step, and can drive simply by the step input.
Features
• Single-channel PWM current control stepping motor driver.
• Output on-resistance (upper side : 0.25Ω ; lower side : 0.15Ω ; total of upper and lower : 0.4Ω ; Ta = 25°C, IO = 4.0A)
• Half, 1/8, 1/16, 1/32, 1/64, 1/128, 1/10, 1/20 Step are selectable.
• Advance the excitation step with the only step signal input.
• BiCDMOS process IC.
• Available forward reverse control.
• IO max=4.0A
• Thermal shutdown circuit.
• Input pull down resistance
• With reset pin and enable pin.
Specifications
Absolute Maximum Ratings at Ta = 25°C
Parameter
Supply voltage
Symbol
Conditions
Ratings
Unit
VM max
50
V
4
A
Output current
IO max
Output peak current
IO peak
Logic input voltage
VIN max
VREF input voltage
VREF max
6
V
MO / DOWN pin input voltage
VMO /VDOWN max
6
V
tw≤10ms, duty 20%
Indipendent IC
4.6
A
6
V
Allowable power dissipation
Pd max
2.45
W
Operating temperature
Topr
-30 to +85
°C
Storage temperature
Tstg
-55 to +150
°C
Caution 1) Absolute maximum ratings represent the value which cannot be exceeded for any length of time.
Caution 2) Even when the device is used within the range of absolute maximum ratings, as a result of continuous usage under high temperature, high current,
high voltage, or drastic temperature change, the reliability of the IC may be degraded. Please contact us for the further details.
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating
Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability.
Semiconductor Components Industries, LLC, 2013
June, 2013
N1611 SY 20111019-S00003 No.A1998-1/23
LV8727
Recommendation Operating Ratings at Ta = 25°C
Parameter
Symbol
Conditions
Ratings
Unit
Supply voltage range
VM
9 to 45
V
Logic input voltage
VIN
0 to 5
V
VREF input voltage range
VREF
0 to 3
V
Electrical Characteristics at Ta = 25°C, VM = 24V, VREF = 1.5V
Parameter
Standby mode current drain
Symbol
Conditions
IMst
ST = “L”
Current drain
IM
ST = “H”, OE = “H”, no load
Thermal shutdown temperature
TSD
Design guarantee
Thermal hysteresis width
ΔTSD
Design guarantee
Logic pin input current
IINL
VIN = 0.8V
IINH
VIN = 5V
Logic high-level input voltage
VINH
Logic low-level input voltage
VINL
Ratings
min
typ
100
μA
3.5
4.9
mA
180
200
°C
70
150
Unit
max
°C
40
3
8
15
μA
30
50
70
μA
0.8
V
3.1
V
0.8
V
2.0
FDT pin high-level voltage
Vfdth
3.5
FDT pin middle-level voltage
Vfdtm
1.1
FDT pin low-level voltage
Vfdtl
Cosc1 = 100pF
V
V
Chopping frequency
Fch
70
100
130
kHz
OSC1 pin charge/discharge current
Iosc1
7
10
13
μA
Chopping oscillation circuit
Vtup1
0.8
1
1.2
V
threshold voltage
Vtdown1
0.3
0.5
0.7
VREF pin input voltage
Iref
VREF = 1.5V
DOWN output residual voltagr
VO1DOWN
Idown = 1mA
MO pin residual voltage
VO1MO
Imo = 1mA
Hold current switching frequency
Fdown
Cosc2 = 1500pF
OSC2 pin charge/discharge current
V
μA
-0.5
50
200
mV
50
200
mV
1.12
1.6
2.08
Hz
Iosc2
7
10
13
μA
Hold current switching frequency
Vtup2
0.8
1
1.2
V
threshold voltage
Vtdown2
0.3
0.5
0.7
V
Output on-resistance
Ronu
IO = 4.0A, high-side ON resistance
0.25
0.325
Ω
Rond
IO = 4.0A, low-side ON resistance
0.15
0.195
Ω
50
μA
1
1.3
V
0.5
0.515
V
Output leakage current
IOleak
VM = 50V
Diode forward voltage
VD
ID = -4.0A
Current setting reference voltage
VRF
VREF = 1.5V, Current ratio 100%
0.485
No.A1998-2/23
LV8727
Package Dimensions
unit : mm (typ)
3236A
29.2
25.6
(22.8)
( 2.5)
4.5
14.5
(14.4)
(11.0)
21.7
18.6 max
(R1.7)
(5.0)
0.4
25
(2.6)
(1.0)
2.0
3.5
1
0.52
4.0
4.2
2.0
SANYO : HZIP25
Pd max - Ta
3.0
Allowable power dissipation, Pd max - W
(12.3)
(8.5)
2.45
2.0
1.27
1.0
0
—30
0
30
60
90
120
Ambient temperature, Ta - C
No.A1998-3/23
TSD
Oscllator
ST
Output pre stage
OSC2
MD1
MD2
OUT1B VM1
VM2 OUT2A
MD3
FR
+
RF2
FDT
OSC1
Decay Mode
setting circuit
Current
select
circuit
OUT2B
STEP RST OE
Output control logic
Output pre stage
Current
select
circuit
+
OUT1A
Output pre stage
SGND
+
-
Regulator 1
RF1
Output pre stage
VREF
PGND2
PGND1
Regulator 2
+
-
DOWN
MO
LV8727
Block Diagram
No.A1998-4/23
LV8727
Pin Assignment
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
RF1
PGND1
OUT1A
VM1
ST
MD1
MD2
MD3
OE
RST
FR
STEP
OSC1
OSC2
FDT
DOWN
MO
VREF
SGND
VM2
OUT2B
PGND2
24
25
OUT2A
2
RF2
1
OUT1B
LV8727
Top view
Pin Functions
Pin No.
Pin Name
Pin Functtion
7
MD1
Excitation mode switching pin
8
MD2
Excitation mode switching pin
9
MD3
Excitation mode switching pin
10
OE
Output enable signal input pin
11
RST
Reset signal input pin
12
FR
Forward / Reverse signal input pin
13
STEP
Clock pulse signal input pin
Equivalent Circuit
Internal 5V
regulator
GND
6
ST
Chip enable input pin.
Internal 5V
regulator
GND
1
OUT1B
Channel 1 OUTB output pin.
2
RF1
Channel 1 current-sense resistor connection pin.
3
PGND1
Channel 1 power GND
4
OUT1A
Channel 1 OUTA output pin.
5
Channel 1 motor supply connect pin
21
VM1
VM2
22
OUT2B
Channel 2 OUTB output pin.
23
PGND2
Channel 2 power GND
24
RF2
Channel 2 current-sense resistor connection pin.
25
OUT2A
Channel 2 OUTA output pin.
5 21
Channel 2 motor supply connect pin
4 25
1 22
3 23
2 24
GND
Continued on next page.
No.A1998-5/23
LV8727
Continued from preceding page.
Pin No.
19
Pin Name
VREF
Pin Functtion
Constant-current control reference voltage input pin.
Equivalent Circuit
Internal 5V
regulator
GND
17
DOWN
Holding current output pin.
18
MO
Position detecting monitor pin.
Internal 5V
regulator
GND
14
OSC1
Chopping frequency setting capacitor connection pin.
15
OSC2
Holding current detection time setting capacitor
Internal 5V
regulator
connection pin.
GND
16
FDT
Decay mode select voltage input
Internal 5V
regulator
GND
No.A1998-6/23
LV8727
Reference describing operation
(1) Stand-by function
When ST pin is at low levels, the IC enters stand-by mode, all logic is reset and output is turned OFF.
When ST pin is at high levels, the stand-by mode is released.
(2) STEP pin function
STEP input advances electrical angle at every nising edge (advances step by step).
Operating mode
Input
ST
STEP
Low
*
Standby mode
High
Excitation step proceeds
High
Excitation step is kept
(3) Excitation setting method
Set the excitation setting as shown in the following table by setting MD1 pin, MD2 pin and MD3 pin.
Input
Initial position
Mode
MD3
MD2
MD1
(Excitation)
1ch current
2ch current
Low
Low
Low
Half
100%
0%
Low
Low
High
1/8
100%
0%
0%
Low
High
Low
1/16
100%
Low
High
High
1/32
100%
0%
High
Low
Low
1/64
100%
0%
High
Low
High
1/128
100%
0%
0%
0%
High
High
Low
1/10
100%
High
High
High
1/20
100%
The initial position is also the default state at start-up and excitation position at counter-reset in each Micro step
resolution.
(4) MO output pin
MO output pin serves as open-drain connection.
If MO pin will be in the state of an initial position, it is turned on, and it outputs a Low level.
Excitation position
MO
Initial position
Low
Other initial position
OPEN
(5) Output current setting
Output current is set shown below by the VREF pin (applied voltage) and a resistance value between RF1(2) pin and
GND.
IOUT = ( VREF / 3 ) / RF1 (2) resistance
* The setting value above is a 100% output current in each excitation mode.
(Example) When VREF = 0.9V and RF1 (2) resistance is 0.1Ω, the setting is shown below.
IOUT = ( 0.9V / 3 ) / 0.1Ω = 3A
No.A1998-7/23
LV8727
(6) Output enable function
When the OE pin is set Low, the output is forced OFF and goes to high impedance. However, the internal logic circuits
are operating, so the excitation position proceeds when the STP is input. Therefore, when OE pin is returned to High,
the output level conforms to the excitation position proceeded by the STEP input.
OE
Operation mode
L
Output: OFF
H
Output: ON
OE
Power save mode
STEP
MO
1ch output
0%
2ch output
Output is high-impedance
(7) Reset function
When the RST pin is set Low, the output goes to initial mode and excitation position is fixed in the initial position for
STEP pin and FR pin input. MO pin outputs at low levels at the initial position. (Open drain connection)
RST
Operation mode
H
Normal operation
L
Reset state
RST
RESET
STEP
MO
1ch output
0%
2ch output
Initial state
No.A1998-8/23
LV8727
(8) Forward / reverse switching function
FR
Operating mode
Low
Clockwise (CW)
High
Counter-clockwise (CCW)
FR
CW mode
CCW mode
CW mode
STEP
Excitation position
(1)
(2)
(3)
(4)
(5)
(6)
(5)
(4)
(3)
(4)
(5)
1ch output
2ch output
The internal D/A converter proceeds by a bit on the rising edge of the step signal input to the STEP pin. In addition,
CW and CCW mode are switched by FR pin setting.
In CW mode, the channel 2 current phase is delayed by 90° relative to the channel 1 current.
In CCW mode, the channel 2 current phase is advanced by 90° relative to the channel 1 current.
(9) DECAY mode setting
Current DECAY method is selectable as shown below by applied voltage to the FDT pin.
FDT voltage
DECAY method
3.5V to
SLOW DECAY
1.1V to 3.1V or OPEN
MIXED DECAY
To 0.8V
FAST DECAY
(10) Chopping frequency setting function
Chopping frequency is set as shown below by a capacitor between OSC1 pin and GND.
Fcp = 1 / ( Cosc1 / 10 х 10-6 ) (Hz)
(Example) When Cosc1 = 180pF, the chopping frequency is shown below.
Fcp = 1 / ( 180 х 10-12 / 10 х 10-6 ) = 55.6(kHz)
No.A1998-9/23
LV8727
(11) Output current in each micro step resolution
Output current vector locus (one step is normalized to 90 degrees)
Half, 1/8, 1/16, 1/32, 1/64, 1/128 Step
Channel 1 current ratio (%)
100.0
66.7
33.3
0.0
0.0
33.3
66.7
100.0
Channel 2 current ratio (%)
Current setting ratio in each micro step resolution
STEP
θ0
θ1
θ2
θ3
θ4
θ5
θ6
θ7
θ8
θ9
θ10
θ11
θ12
θ13
θ14
θ15
θ16
θ17
θ18
θ19
θ20
θ21
θ22
θ23
θ24
θ25
1/128 (%)
1ch
2ch
100
0
100
1
100
2
100
4
100
5
100
6
100
7
100
9
100
10
99
11
99
12
99
13
99
15
99
16
99
17
98
18
98
20
98
21
98
22
97
23
97
24
97
25
96
27
96
28
96
29
95
30
1/64 (%)
1ch
2ch
100
0
100
2
100
5
100
7
100
10
99
12
99
15
99
17
98
20
98
22
97
24
96
27
96
29
1/32 (%)
1ch
2ch
100
0
100
5
100
10
99
15
98
20
97
24
96
29
1ch
100
1/16 (%)
2ch
0
100
10
98
20
96
29
1/8 (%)
1ch
2ch
100
0
98
Half (%)
1ch
2ch
100
0
20
Continued on next page.
No.A1998-10/23
LV8727
Continued from preceding page.
STEP
θ26
θ27
θ28
θ29
θ30
θ31
θ32
θ33
θ34
θ35
θ36
θ37
θ38
θ39
θ40
θ41
θ42
θ43
θ44
θ45
θ46
θ47
θ48
θ49
θ50
θ51
θ52
θ53
θ54
θ55
θ56
θ57
θ58
θ59
θ60
θ61
θ62
θ63
θ64
θ65
θ66
θ67
θ68
θ69
θ70
θ71
θ72
θ73
θ74
θ75
θ76
θ77
θ78
θ79
θ80
θ81
θ82
θ83
θ84
θ85
θ86
θ87
θ88
θ89
θ90
1/128 (%)
1ch
2ch
95
31
95
33
94
34
94
35
93
36
93
37
92
38
92
39
91
41
91
42
90
43
90
44
89
45
89
46
88
47
88
48
87
49
86
50
86
51
85
52
84
53
84
55
83
56
82
57
82
58
81
59
80
60
80
61
79
62
78
62
77
63
77
64
76
65
75
66
74
67
73
68
72
69
72
70
71
71
70
72
69
72
68
73
67
74
66
75
65
76
64
77
63
77
62
78
62
79
61
80
60
80
59
81
58
82
57
82
56
83
55
84
53
84
52
85
51
86
50
86
49
87
48
88
47
88
46
89
45
89
1/64 (%)
1ch
2ch
95
31
1/32 (%)
1ch
2ch
94
34
94
34
93
36
92
38
92
38
91
41
90
43
90
43
89
45
88
47
88
47
87
49
86
51
86
51
84
53
83
56
83
56
82
58
80
60
80
60
79
62
77
63
77
63
76
65
74
67
74
67
72
69
71
71
71
71
69
72
67
74
67
74
65
76
63
77
63
77
62
79
60
80
60
80
58
82
56
83
56
83
53
84
51
86
51
86
49
87
47
88
47
88
45
89
1/16 (%)
1ch
2ch
1/8 (%)
1ch
2ch
92
38
92
38
88
47
83
56
83
56
77
63
71
71
71
71
63
77
56
83
56
83
47
88
Halfe (%)
1ch
2ch
71
71
Continued on next page.
No.A1998-11/23
LV8727
Continued from preceding page.
STEP
θ91
θ92
θ93
θ94
θ95
θ96
θ97
θ98
θ99
θ100
θ101
θ102
θ103
θ104
θ105
θ106
θ107
θ108
θ109
θ110
θ111
θ112
θ113
θ114
θ115
θ116
θ117
θ118
θ119
θ120
θ121
θ122
θ123
θ124
θ125
θ126
θ127
θ128
1/128 (%)
1ch
2ch
44
90
43
90
42
91
41
91
39
92
38
92
37
93
36
93
35
94
34
94
33
95
31
95
30
95
29
96
28
96
27
96
25
97
24
97
23
97
22
98
21
98
20
98
18
98
17
99
16
99
15
99
13
99
12
99
11
99
10
100
9
100
7
100
6
100
5
100
4
100
2
100
1
100
0
100
1/64 (%)
1ch
2ch
1/32 (%)
1ch
2ch
43
90
43
90
41
91
38
92
38
92
36
93
34
94
34
94
31
95
29
96
29
96
27
96
24
97
24
97
22
98
20
98
20
98
17
99
15
99
15
99
12
99
10
100
10
100
7
100
5
100
5
100
2
100
0
100
0
100
1/16 (%)
1ch
2ch
1/8 (%)
1ch
2ch
38
92
38
92
29
96
20
98
20
98
10
100
0
100
0
100
Half (%)
1ch
2ch
0
100
No.A1998-12/23
LV8727
Output current vector locus (one step is normalized to 90 degrees)
1/10, 1/20 STEP
Channel 1 current ratio (%)
100.0
66.7
33.3
0.0
0.0
33.3
66.7
100.0
Channel 2 current ratio (%)
Current setting ratio in each micro step resolution
1/10, 1/20 STEP
STEP
θ0
θ1
θ2
θ3
θ4
θ5
θ6
θ7
θ8
θ9
θ10
θ11
θ12
θ13
θ14
θ15
θ16
θ17
θ18
θ19
θ20
1/20 (%)
1ch
2ch
100
0
100
8
99
16
97
23
95
31
92
38
89
45
85
52
81
59
76
65
71
71
65
76
59
81
52
85
45
89
38
92
31
95
23
97
16
99
8
100
0
100
1/10 (%)
1ch
2ch
100
0
99
16
95
31
89
45
81
59
71
71
59
81
45
89
31
95
16
99
0
100
No.A1998-13/23
LV8727
(12) Current wave example in each micro step resolution (Half, 1/16, 1/128, 1/20 STEP)
Half STEP (CW mode)
STEP
MO
(%)
100
I1
0
-100
(%)
100
I2
0
-100
1/16 STEP (CW mode)
STEP
MO
(%)
100
50
I1
0
-50
-100
(%)
100
50
I2
0
-50
-100
No.A1998-14/23
LV8727
1/128 STEP ( CW mode )
STEP
MO
(%)
100
50
I1
0
-50
-100
(%)
100
50
I2
0
-50
-100
1/20 STEP ( CW mode )
STEP
MO
(%)
100
50
I1
0
-50
-100
(%)
100
50
I2
0
-50
-100
No.A1998-15/23
LV8727
(13) Current control operation
SLOW DECAY current control operation
When FDT pin voltage is a voltage over 3.5V, the constant-current control is operated in SLOW DECAY mode.
( Sine-wave increasing direction )
STEP
Setting current
Setting current
Coil current
Chopping period
Blanking Time
Current mode CHARGE
SLOW
CHARGE
SLOW
( Sine-wave decreasing direction )
STEP
Setting current
Coil current
Setting current
Chopping period
Chopping period
Blanking Time
Current mode CHARGE
SLOW
Blanking Time
SLOW
Blanking Time
SLOW
Each of current modes operates with the follow sequence.
The IC enters CHARGE mode at a rising edge of the chopping oscillation. ( A period of CHARGE mode (Blanking
Time) is forcibly present in approximately 1μs, regardless of the current value of the coil current (ICOIL) and set
current (IREF)).
After the period of the blanking time, the IC operates in CHARGE mode until ICOIL ≥ IREF. After that, the mode
switches to the SLOW DECAY mode and the coil current is attenuated until the end of a chopping period.
At the constand-current in SLOW DECAY mode, following to the setting current from the coil current may take time
(or not follow) for the current delay attenuation.
No.A1998-16/23
LV8727
FAST DECAY current control operation
When FDT pin voltage is a voltage under 0.8V, the constant-current control is operated in FAST DECAY mode.
(Sine-wave inxreasing direction)
STEP
Setting current
Setting current
Coil current
Chopping period
Blanking Time
Current mode
CHARGE
FAST
CHARGE
FAST
(Sine-wave decreasing direction)
STEP
Setting current
Coil current
Setting current
Chopping period
Blanking Time
Current mode
CHARGE
FAST
Blanking Time
FAST
CHARGE
FAST
Each of current modes operates with the follow sequence.
The IC enters CHARGE mode at a rising edge of the chopping oscillation. ( A period of CHARGE mode (Blanking
Time) is forcibly present in approximately 1μs, regardless of the current value of the coil current (ICOIL) and set
current (IREF)).
After the period of the blanking time, the IC operates in CHARGE mode until ICOIL ≥ IREF. After that, the mode
switches to the FAST DECAY mode and the coil current is attenuated until the end of a chopping period.
At the constand-current control in FAST DECAY mode, following to the setting current from the coil current take
short-time for the current fast attenuation, but, the current ripple value may be higher.
No.A1998-17/23
LV8727
MIXED DECAY current control operation
When FDT pin voltage is a voltage between 1.1V to 3.1V or OPEN, the constant-current control is operated in MIXED
DECAY mode.
(Sine-wave increasing direction)
STEP
Setting current
Setting current
Coil current
Chopping period
Blanking Time
Current mode CHARGE
SLOW
FAST
CHARGE
SLOW
FAST
(Sine-wave decreasing direction)
STEP
Setting current
Coil current
Setting current
Chopping period
Blanking Time
Current mode CHARGE
SLOW
FAST
Blanking Time
FAST
CHARGE
SLOW
Each of current modes operates with the follow sequence.
The IC enters CHARGE mode at a rising edge of the chopping oscillation. ( A period of CHARGE mode (Blanking
Time) is forcibly present in approximately 1μs, regardless of the current value of the coil current (ICOIL) and set
current (IREF)).
In a period of Blanking Time, the coil current (ICOIL) and the setting current (IREF) are compared.
If an ICOIL < IREF state exists during the charge period:
The IC operates in CHARGE mode until ICOIL ≥ IREF. After that, it switches to SLOW DECAY mode and
then switches to FAST DECAY mode in the last approximately 1μs of the period.
If no ICOIL < IREF state exists during the charge period:
The IC switches to FAST DECAY mode and the coil current is attenuated with the FAST DECAY operation
until the end of a chopping period.
The above operation is repeated. Normally, in the sine wave increasing direction the IC operates in SLOW (+ FAST)
DECAY mode, and in the sine wave decresing direction the IC operates in FAST DECAY mode until the current is
attenuated and reaches the set value and the IC operates in SLOW (+ FAST) DECAY mode.
No.A1998-18/23
LV8727
(13) Output short-circuit protection circuit
Built-in output short-circuit protection circuit makes output to enter in stand-by mode. This function prevents the IC
from damaging when the output shorts circuit by a voltage short or a ground short, etc. When output short state is
detected, short-circuit detection circuit state the operating and output is once turned OFF. Subsequently, the output is
turned ON again after the timer latch period ( typ. 256μs ). If the output remains in the short-circuit state, turn OFF the
output, fix the output to the wait mode, and turn ON the EMO output.
When output is fixed in stand-by mode by output short protection circuit, output is released the latch by setting ST =
“L”.
Output ON
H-bridge
output state
Short-circuit
detection state
Output ON
Short- Release
circuit
Output OFF
Standby state
Short-circuit
Internal counter
1st counter
start
1st counter 1st counter
stop
start
1st counter
end
2nd counter
start
2nd counter
end
No.A1998-19/23
LV8727
(15) DOWN output pin
The DOWN output pin is an open-drain connection.
This pin is turned ON when no rising edge of STEP between the input signals while a period determined by a
capacitor between OSC2 and GND, and outputs at low levels.
The open-drain output in once turned ON, is turned OFF at the next rising edge of STEP.
Holding current switching time ( Tdown ) is set as shown below by a capacitor between OSC2 pin and GND.
Tdown = Cosc2 х 0.4 х 109 (s)
(Example) When Cosc2 = 1500pF, the STEP signal detection time is shown below.
Tdown = 1500pF х 0.4 х 109 = 0.6 (s)
Rotation
Motor keep
Rotation
STEP input
Tdown
DOWN output
OFF
Low
OFF
By connecting circumference parts like the example of the following circuit diagram using a DOWN pin, that is a STEP
signal is not inputted more than detection time, it is a DOWN output's turning on in the state of holding turning on
electricity the position of a stepping motor, and setting current's falling because VREF input voltage's falls, and
stopping power consumption -- it can do.
R1
VREF
R3
R2
DOWN
(Example) When V1=5V, R1=27kΩ, R2=4.7kΩ, R3=1kΩ, the VREF input voltage is shown below.
DOWN output OFF: VREF=V1×R2/(R1+R2)=0.741V
DOWN output ON: VREF=V1×(R2║R3)/ (R1+(R2║R3))=0.126V
No.A1998-20/23
LV8727
Application Circuit Example
PGND1
OUT1A
VM1
ST
MD1
MD2
MD3
OE
RST
FR
STEP
OSC1
OSC2
FDT
DOWN
MO
VREF
SGND
VM2
OUT2B
PGND2
RF2
OUT2A
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
+
-
Logic input
- +
180pF
RF1
1
- +
OUT1B
LV8727
Logic
supply
M
Motor connect pin
The above sample application circuit is set to the following conditions:
· Constant-current setting
IOUT=VREF/3/RF
(Example) When is VREF=0.9V
IOUT=0.9V/3/0.1Ω=3A
· Chopping frequency setting
Fchop=Ichop/(Cchop×Vt×2)
=10µA/(180pF×0.5V×2)=55.6kHz
No.A1998-21/23
LV8727
HZIP25 Heat sink attachment
Heat sinks are used to lower the semiconductor device junction temperature by leading the head generated by the device to
the outer environment and dissipating that heat.
a. Unless otherwise specified, for power ICs with tabs and power ICs with attached heat sinks, solder must not be
applied to the heat sink or tabs.
b.
Heat sink attachment
· Use flat-head screws to attach heat sinks.
· Use also washer to protect the package.
· Use tightening torques in the ranges 39-59Ncm(4-6kgcm) .
· If tapping screws are used, do not use screws with a diameter larger
than the holes in the semiconductor device itself.
· Do not make gap, dust, or other contaminants to get between the
semiconductor device and the tab or heat sink.
· Take care a position of via hole .
· Do not allow dirt, dust, or other contaminants to get between the
semiconductor device and the tab or heat sink.
· Verify that there are no press burrs or screw-hole burrs on the heat sink.
· Warping in heat sinks and printed circuit boards must be no more than
0.05 mm between screw holes, for either concave or convex warping.
· Twisting must be limited to under 0.05 mm.
· Heat sink and semiconductor device are mounted in parallel.
Take care of electric or compressed air drivers
· The speed of these torque wrenches should never exceed 700 rpm, and
should typically be about 400 rpm.
Binding head
machine screw
Countersunk head
mashine screw
Heat sink
gap
Via hole
c.
Silicone grease
· Spread the silicone grease evenly when mounting heat sinks.
· Recommends YG-6260 (Momentive Performance Materials Japan LLC)
d.
Mount
· First mount the heat sink on the semiconductor device, and then mount that assembly on the printed circuit board.
· When attaching a heat sink after mounting a semiconductor device into the printed circuit board, when tightening
up a heat sink with the screw, the mechanical stress which is impossible to the semiconductor device and the pin
doesn't hang.
e.
When mounting the semiconductor device to the heat sink using jigs, etc.,
· Take care not to allow the device to ride onto the jig or positioning dowel.
· Design the jig so that no unreasonable mechanical stress is not applied to the semiconductor device.
f.
Heat sink screw holes
· Be sure that chamfering and shear drop of heat sinks must not be larger than the diameter of screw head used.
· When using nuts, do not make the heat sink hole diameters larger than the diameter of the head of the screws used.
A hole diameter about 15% larger than the diameter of the screw is desirable.
· When tap screws are used, be sure that the diameter of the holes in the heat sink are not too small. A diameter about
15% smaller than the diameter of the screw is desirable.
g.
There is a method to mount the semiconductor device to the heat sink by using a spring band. But this method is not
recommended because of possible displacement due to fluctuation of the spring force with time or vibration.
No.A1998-22/23
LV8727
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PS No.A1998-23/23