SANKEN ELECTRIC CO., LTD.
http://www.sanken-ele.co.jp/en/
SLA7070MPRT Series Unipolar 2-Phase
Stepper Motor Driver ICs
Application Information
SLA7070MPRT-AN, Rev. 1.4
General Description
This document describes the SLA7070MPRT series,
which are unipolar 2-phase stepping motor driver ICs. The
SLA7070MPRT series employs a clock input method as
a control signal input method, enabling full control of the
device operation using only a few signal lines, instead of
the conventional phase input method that requires about 10
signal lines. This allows simplification of the circuit design
and a reduced workload on the control microprocessor.
In addition, the SLA7070MPRT series is improved in its
reliability by preventing the IC from damage due to abnor-
mal conditions. For example, it has a flag output terminal
to signal that a protection circuit has operated. The series
also has a built-in protection circuitry against motor coil
opens/shorts and thermal shutdown protection as well.
All the SLA7070MPRT series ICs are compatible in their
pin layouts and interface specifications, allowing custom-
ers the flexibility of choosing the IC that is optimal for the
target equipment characteristics.
Features and Benefits
• Power supply voltages, VBB : 46 V (max.), 10 to 44 V
normal operating range
• Logic supply voltages, VDD : 3.0 to 5.5 V
• Maximum output currents: 1 A, 1.5 A, 2 A, 3 A
• Built-in sequencer
• Full-, half-, and microstepping available (microstepping
options are capable of full-, half-, quarter-, eighth-, and
sixteenth-stepping
Figure 1. SLA7070MPRT packages are fully molded ZIPs with an
exposed pad for heatsink mounting.
The SLA7070MMPR series product variants and optional features
Part Number Stepping
Rate
Output Current
(IOUT)
(A)
Input Clock
Edge Detection
Blanking Time
(μs)
Standard Standard
SLA7070MPRT
Full and
half step
1
Rising (positive)
edge 3.2
SLA7071MPRT 1.5
SLA7072MPRT 2
SLA7073MPRT 3
SLA7075MPRT
Microstep
1
Rising (positive)
edge 1.7
SLA7076MPRT 1.5
SLA7077MPRT 2
SLA7078MPRT 3
• Built-in sense resistor, RSInt
• All variants are pin-compatible for enhanced
design flexibility
• ZIP type 23-pin molded package (SLA package)
• Self-excitation PWM current control with fixed off-time
(microstepping options off-time adjusted automatically by
step reference current ratio; 3 levels)
• Built-in synchronous rectifying circuit reduces losses at
PWM-off
• Synchronous PWM chopping function prevents motor
noise in Hold mode
• Sleep mode for reducing the IC input current in
stand-by state
• Built-in protection circuitry against motor coil
opens/shorts and thermal shutdown protection options
Applications
• LBPs, PPCs, ATMs, industrial robots, and so forth
January 10, 2013
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SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Table of Contents
Specifications 3
Functional Block Diagrams 3
Pin Descriptions 3
Package Outline Drawing 5
Electrical Characteristics 6
Allowable Power Dissipation 10
Typical Application 11
Device Logic 12
Pin Logic and Timing 12
Common Input Pins 12
Monitor Output Pin 12
Logic Input Pins 13
Clock Edge Timing 13
Reset Release and Clock Input Timing 13
Logic Level Change 13
Stepping Sequence Diagrams 14
Motor Excitation Sequencing 21
Individual Circuit Descriptions 22
Monolithic IC (MIC) 22
Output MOSFET Chip 22
Sense Resistor 22
Functional Description 23
PWM Current Control 23
Blanking Time 23
PWM Off-Time 26
Protection Functions 27
Application Information 29
Motor Current Ratio Setting (R1, R2, RS) 29
Lower Limit of Control Current 29
Avalanche Energy 29
On-Off Sequence of Power Supply (VBB
and VDD) 30
Motor Supply Voltage (VM) and Main Power
Supply Voltage (VBB) 31
Internal Logic Circuits 31
Reset 31
Clock Input 31
Chopping Synchronous Circuit 31
Output Disable (Sleep1 and Sleep2) Circuits 31
Ref/Sleep1 Pin 32
Logic Input Pins 32
Thermal Design Information 32
Characteristic Data 34
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SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Functional Block Diagrams
SLA7070MPRT to SLA7073MPRT: Full and Half step
Sequencer
and
Sleep Circuit
Synchro
Control
PWM
Control
OSC
Comp
+
-
DAC
Pre-
Driver
PWM
Control
OSC
DAC
Pre-
Driver
+
-
MIC
SLA707xMPRT
Reg.
OutA
OutA
OutA
OutA
OutB
OutB
OutB
OutB
V
DD
Ref/Sl eep1
Flag
N.C.
M1
M2
M3
CW/CCW
Cl ock
Reset
V
BB
SenseBSenseA
GndSync
Rs Rs
1234
5
6789 10 11
12
1314 1516
17
18
19
20 21 22 23
Protect Protect
TSD
Comp
Pin Number. Symbol Function
1, 2 OutA Output of phase A
3, 4 ¯
O
¯
¯
u
¯
¯
t
¯
¯
A
¯ Output of phase A
¯
5 SenseA Phase A current sensing
6 N.C. No connection
7M1
Commutation and Sleep2 setting8M2
9M3
10 Clock Step clock input
11 VBB Main power supply (for motor)
12 Gnd Ground
13 Ref/Sleep1 Input for control current and Sleep1 setting
14 VDD Power supply to logic
15 Reset Reset for internal logic
16 CW/CCW Forward/reverse switch input
17 Sync Synchronous PWM control switch input
18 Flag Output from protection circuits monitor
19 SenseB Phase B current sensing
20, 21 ¯
O
¯
¯
u
¯
¯
t
¯
¯
B
¯ Output of phase B
¯
22, 23 OutB Output of phase B
1357911131517192123
2 4 6 8 10 12 14 16 18 20 22
Pad Side
4
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Sequencer
and
Sleep Circuit
Synchro
Control
PWM
Control
OSC
+
-
DAC
Pre-
Driver
PWM
Control
OSC
DAC
Pre-
Driver
+
-
Reg.
OutA
OutA
OutA
OutA
OutB
OutB
OutB
OutB
V
DD
Ref/Sleep1
Flag
MO
M1
M2
M3
Clock
Res et
V
BB
SenseBSenseA
GndSync
Rs Rs
1234
5
6 7 8 9 10 11
12
1314 1516
17
18
19
20 21 22 23
Protect Protect
TSD
CW/CCW
Comp Comp
MIC
SLA707xMPRT
SLA7075MPRT to SLA7078MPRT: Microstep
Pin Number. Symbol Function
1, 2 OutA Output of phase A
3, 4 ¯
O
¯
¯
u
¯
¯
t
¯
¯
A
¯ Output of phase A
¯
5 SenseA Phase A current sensing
6M
O2-phase commutation status monitor output
7M1
Commutation and Sleep2 setting8M2
9M3
10 Clock Step clock input
11 VBB Main power supply (for motor)
12 Gnd Ground
13 Ref/Sleep1 Input for control current and Sleep1 setting
14 VDD Power supply to logic
15 Reset Reset for internal logic
16 CW/CCW Forward/reverse switch input
17 Sync Synchronous PWM control switch input
18 Flag Output from protection circuits monitor
19 SenseB Phase B current sensing
20, 21 ¯
O
¯
¯
u
¯
¯
t
¯
¯
B
¯ Output of phase A
¯
22, 23 OutB Output of phase B
1357911131517192123
2 4 6 8 10 12 14 16 18 20 22
Pad Side
5
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Leadframe plating Pb-free. Device composition
includes high-temperature solder (Pb >85%),
which is exempted from the RoHS directive.
1.7 ±0.1
4.8 ±0.2
16.4 ±0.2
31 ±0.2
24.4 ±0.2
F3.2 ±0.15
12.9 ±0.2
0.65 +0.2
-0.1
16 ±0.2
9.9 ±0.2
4-(R1)
5±0.5
0.55+0.2
-0.1
0.55+1
-0.5
4.5
22 × P1.27±0.5 = 27.94±1
±0.7
R-end
31.3 ±0.2
123410
115678912
13
14
15
16
17
18
19
20
21
22
23
(Includes Mold Flash)
2.45 ±0.2
(Measured at
Base of Pins)
(Measured at Pin Tips)
Unit: mm
Pin material: Cu
Pin Plating: Solder plating (Pb free)
a: Item name 1: SLA707xMRT (x is 0 to 3, or 5 to 8; last digit
of part number, corresponding to current rating and stepping rate
)
b: Item name 2: P
c: Lot number:
1st letter is last digit of year
2nd letter is month
January to September: 1 to 9
October: O
November: N
December: D
3rd and 4th are date of manufacture (01 to 31)
(Measured at
Pin Tips)
(Heatsink Pad)
Gate Flash
Japan
a
bc
(4.3)
F3.2 ±0.15 x 3.8
Package Outline Drawing, SLA 23-Pin
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SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Recommended Operating Conditions Unless specifically noted, TA is 25°C
Characteristic Symbol Test Conditions Min. Typ. Max. Unit
Load (Motor Supply) Voltage VM– – 44 V
Main Power Supply Voltage VBB 10 – 44 V
Logic Supply Voltage VDD
Surge voltage at VDD pin should
be less than ±0.5 V to avoid
malfunctioning in operation
3.0 – 5.5 V
Case Temperature TcMeasured at pin 12, without
heatsink – – 90 °C
Electrical Characteristics
• This section provides separate sets of electrical characteristic data for each product.
• The polarity value for current specifies a sink as "+ ," and a source as “,” referencing the IC.
• Please refer to the datasheet of each product for additional details.
Absolute Maximum Ratings Unless specifically noted, TA is 25°C
Characteristic Symbol Notes Rating Unit
Load (Motor Supply) Voltage VM46 V
Main Power Supply Voltage VBB 46 V
Logic Supply Voltage VDD
6V
1 s (5% duty) 7 V
Output Current IO
SLA7070MPRT
SLA7075MPRT
Control current value
1.0 A
SLA7071MPRT
SLA7076MPRT 1.5 A
SLA7072MPRT
SLA7077MPRT 2.0 A
SLA7073MPRT
SLA7078MPRT 3.0 A
Logic Input Voltage VIN 0.3 to VDD+0.3 V
REF Input Voltage VREF 0.3 to VDD+0.3 V
Sense Voltage VRS ±1 V
Power Dissipation PDWithout heatsink 4.7 W
Junction Temperature TJ150 °C
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SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Electrical Characteristics Common to All Variants Unless specifically noted, TA is 25°C
Characteristic Symbol Test Conditions Min. Typ. Max. Unit
Main Power Supply Current IBB Normal mode – – 15 mA
IBBS Sleep1 and Sleep2 mode – – 100 A
Logic Power Current IDD ––5mA
MOSFET Breakdown Voltage VDSS VBB = 44 V, ID = 1 mA 100 – – V
Maximum Response Frequency fclk Clock duty = 50% 250 – – KHz
Logic Supply Voltage VIL – – 0.25 × VDD V
VIH 0.75 × VDD ––V
Logic Supply Current IIL –±1–A
IIH –±1–A
REF Input Voltage1VREF See figure 1 – – – V
VREFS Output off, Sleep1 mode 2.0 – VDD V
REF Input Current IREF – ±10 – A
SENSE Voltage VSENSE VREF = 0 to 1.5 V
Step reference current ratio: 100%
VREF –
0.03 –VREF –
0.03 V
Sleep to Enable Recovery Time tSE Sleep1 and Sleep2 100 – – s
Switching Time tcon Clock edge to output on – 2.0 – s
tcoff Clock edge to output off – 1.5 – s
Overcurrent Detection Voltage2VOCP At motor coil short-circuit 0.65 0.7 0.75 V
Overcurrent Detection Current
( VOCP / RS
)IOCP
SLA7070MPRT, SLA7075MPRT,
SLA7071MPRT, SLA7076MPRT – 2.3 – A
SLA7072MPRT, SLA7077MPRT – 3.5 – A
SLA7073MPRT, SLA7078MPRT – 4.6 – A
Load Disconnection Undetected Time topp From PWM off – 2 – s
Overheat Protection Temperature Ttsd Measured at back of device case (after heat
has saturated) – 140 – °C
Flag Output Voltage
VFlagL IFlagL = 1.25 mA – – 1.25 V
VFlagH IFlagH = –1.25 mA VDD –
1.25 ––V
Flag Output Current IFlagL – – 1.25 mA
IFlagH –1.25 – – mA
1In a state of: Sleep1, IBBS, output off, and Sequencer enabled.
2In a condition of VSENSE VOCP , the protection circuit will activate.
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SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Electrical Characteristics Varying with Stepping Sequence Unless specifically noted, TA is 25°C, VBB = 24 V, VDD = 5 V
SLA7070MPRT, SLA7071MPRT, SLA7072MPRT, and SLA7073MPRT (Full- and Half-Stepping)
Characteristic Symbol Test Conditions Min. Typ. Max. Unit
Step Reference Current Ratio Mode F VREF VSENSE = 100 V,
VREF = 0 to 1.0 V
– 100 – %
Mode 8 – 70 – %
PWM Minimum On-Time ton(min) – 3.2 – s
PWM Off-Time toff –12–s
SLA7075MPRT, SLA7076MPRT, SLA7077MPRT, and SLA7078MPRT (Microstepping)
Step Reference Current Ratio
Mode F
VREF VSENSE = 100 V,
VREF = 0 to 1.0 V
– 100 – %
Mode E – 98.1 – %
Mode D – 95.7 – %
Mode C – 92.4 – %
Mode B – 88.2 – %
Mode A – 83.1 – %
Mode 9 – 77.3 – %
Mode 8 – 70.7 – %
Mode 7 – 63.4 – %
Mode 6 – 55.5 – %
Mode 5 – 47.1 – %
Mode 4 – 38.2 – %
Mode 3 – 29 – %
Mode 2 – 19.5 – %
Mode 1 – 9.8 – %
MO (Load) Output Voltage VMOL IMOL = 1.25 mA – – 1.25 V
VMOH IMOH = –1.25 mA VDD – 1.25 – – V
MO (Load) Output Current IMOL – – 1.25 mA
IMOH –1.25 – – mA
PWM Minimum On-Time ton(min) – 1.7 – s
PWM Off-Time
toff1 Mode 8, 9, A, B, C, D, E, and F – 12 – s
toff2 Mode 4, 5, 6, and 7 – 9 – s
toff3 Mode 1, 2, and 3 – 7 – s
9
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Electrical Characteristics Varying with Output Current Range Unless specifically noted, TA is 25°C, VBB = 24 V, VDD = 5 V
SLA7070MPRT and SLA7075MPRT (IO = 1.0 A)
Characteristic Symbol Test Conditions Min. Typ. Max. Unit
Output On-Resistance RDS(on) ID = 1 A – 0.7 0.85
Body Diode Forward Voltage VfIf = 1 A – 0.85 1.1 V
Sense Resistor* RS±3% tolerance 0.296 0.305 0.314
REF Input Voltage VREF Within specified current limit, IO = 1.0 A 0.04 – 0.3 V
SLA7071MPRT and SLA7076MPRT (IO = 1.5 A)
Output On-Resistance RDS(on) ID = 1.5 A – 0.45 0.6
Body Diode Forward Voltage VfIf = 1.5 A – 1.0 1.25 V
Sense Resistor* RS±3% tolerance 0.296 0.305 0.314
REF Input Voltage VREF Within specified current limit, IO = 1.5 A 0.04 – 0.45 V
SLA7072MPRT and SLA7077MPRT (IO = 2.0 A) Electrical Characteristics
Output On-Resistance RDS(on) ID = 2 A – 0.25 0.4
Body Diode Forward Voltage VfIf = 2 A – 0.95 1.2 V
Sense Resistor* RS±3% tolerance 0.199 0.205 0.211
REF Input Voltage VREF Within specified current limit, IO = 2.0 A 0.04 – 0.4 V
SLA7073MPRT and SLA7078MPRT (IO = 3.0 A) Electrical Characteristics
Output On-Resistance RDS(on) ID = 3 A – 0.18 0.24
Body Diode Forward Voltage VfIf = 3 A – 0.95 2.1 V
Sense Resistor* RS±3% tolerance 0.150 0.155 0.160
REF Input Voltage VREF Within specified current limit, IO = 3.0 A 0.04 – 0.45 V
*Includes the inherent bulk resistance (approximately 5 m) of the resistor itself.
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SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
V
OCP =0.7V
0.3V
VDD
0V
2.0V
Sleep
Prohibition Zone
1 Set Range
0.4V
0.45V
1.0 A
Devices 2.0 A
Devices 1.5 A and
3.0 A
Devices
Motor Current Set Range*
*Motor Current Set Range is determined
by the value of the resistor built into the device.
Figure 1. Reference Voltage Setting (VREF, REF/SLEEP1 Pin). Please pay extra
attention to the change-over between the motor current specification range, IMO
, and
the Sleep1 Set Range. VOCP falls on the "prohibition zone" threshold. If the change-
over time is too slow, OCP operation will start when VSInt > VOCP.
4ǰLC
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#ODKGPV6GORGTCVWTG6 #= ?
#NNQYCDNG2QYGT&KUUKRCVKQP2&=9 ?
Figure 2. Allowable Power Dissipation
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SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
SLA7075MPRT
SLA7076MPRT
SLA7077MPRT
SLA7078MPRT
VBBOutA OutA OutBOutB
VDD
Clock
Sync
CW/CCW
Ref/Sleep
Sense B
Sense AGnd
R1
R3R2
Sleep
Q1
CA
CB
Vs=10 to 44 V
VCC =3.0 5to .5V
Logic Gnd Power Gnd
Pin12
Gnd
Reset/Sleep1
M1
M2
M3
Mo
Flag
C1
C2
Micro-
controller
Typical Application
(Microstepper Variants)
External Component Typical Values
(for reference use only):
Component Value Component Value
R1 10 kCA 100 F / 50 V
R2 1 k (varistor) CB 10 F / 10 V
R3 10 kC1 0.1 F
• Take precautions to avoid noise on the VDD line; noise
levels greater than 0.5 V on the VDD line may cause device
malfunction. Noise can be reduced by separating the logic
ground and the power ground on a PCB from the GND pin
(pin 12).
• Unused logic input pins (CW / CCW, M1, M2, M3, Reset,
and SYNC) must be pulled up or down to VDD or ground. If
those unused pins are left open, the device malfunctions.
• Unused logic output pins (Mo, Flag) must be kept open.
Figure 3. Typical Application Circuit
12
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Truth Tables
Common Input Pins
Table 1 shows the truth table for input pins common to both
half/full step and microstep variants of the SLA7070MPRT
series.
• The Reset function is asynchronous. If the input on the Reset
pin is high, the internal logic circuit is reset. At this point, if the
Ref pin stays low, then the DMOS outputs turn on at the starting
point of excitation. Note that the Disable control functions are not
available with the Reset pin signal set high.
• Voltage at the Ref / Sleep1 pin controls the PWM current and
the Sleep1 function. For normal operation, VREF should be below
1.5 V (low level). Applying a voltage greater than 2.0 V (high
level) to the Ref / Sleep1 pin disables the outputs and puts the
motor in a free state (coast). This function is used to minimize
power consumption when the device is not in use. Although
it disables much of the internal circuitry, including the out-
put MOSFETs and regulator, the sequencer / translator circuit
remains active.
• The Sync function is active only for 2-phase excitation timing.
If this function is used during other than 2-phase excitation tim-
ing, the overall stepping sequence might collapse because PWM
off-time and set current are different in each phase A and phase
B control scenario. (2-phase excitation timing is when the step
reference current ratio of both phase A and phase B is Mode 8.)
Commutation/Sleep2 Function
Table 2 shows the logic of the pins (M1, M2, and M3) which set
commutation. In the Sleep2 function, the outputs are disabled and
the driver supply current (IBB) is reduced. However, unlike the
Sleep1 function, the logic circuitry is put into a standby state and
therefore the sequencer / translator circuit is not active.
Note: When awakening from Sleep2 mode, a delay of 100 s or
longer before sending a Clock pulse is recommended.
Monitor Output Pin
The SLA7070MPRT series provides two device status monitor
outputs:
• Flag pin – Protection feature operation
• Mo pin (microstep variants only) – Stepping sequence
Table 3 shows the logic for the monitor pins. The outputs turn off
when the protection circuit starts operating. To release the protec-
tion state, cycle (set low, and then high) the logic supply voltage
(VDD).
Table 1. Truth Table for Common Input Pins (Half/Full and Microstep)
Pin Name Low Level High Level Clock
Reset Normal operation Logic reset
(Positive Edge)
CW/CCW Forward (CW) Reverse (CCW)
M1, M2, M3 Commutation (Sleep2 is not included)
Ref / Sleep1 Normal operation Sleep1 function
Sync Non-sync PWM control Sync PWM control
Table 2. Commutation-Sleep2 Truth Table for
Common Input Pins (Half/Full and Microstep)
Pin Name Full / Half Step Microstep
M1 M2 M3
L L L Full step (Mode 8 fixed) Full step (Mode 8 fixed)
H L L Full step (Mode F fixed) Full step (Mode F fixed)
L H L Half step Half step
H H L Half step (Mode F fixed) Half step (Mode F fixed)
LLH
Sleep2 function
Quarter step
H L H Eighth step
L H H Sixteenth step
H H H Sleep2 function
Table 3. Monitor Output Pins Logic
Pin Name Low Level High Level
Flag Normal operation Protection circuit operation
Mo Other than 2-phase
excitation timing 2-phase excitation timing
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SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Logic Input Pins
The low pass filter incorporated with the logic input pins (Reset,
Clock, CW/CCW, M1, M2, M3, and Sync) improves noise rejec-
tion. The logic inputs are CMOS input compatible, and therefore
they are in a high impedance state. Use the IC at a fixed input
level, either low or high.
Input Logic Timing
Clock Signal
A low-to-high then high-to-low transition on the Clock input
advances the sequencer / translator. The Clock pulse width should
be set at 2 s in both positive and negative polarities. Therefore,
clock response frequency should be 250 kHz. Only the positive
edge is used for timing, however, it is necessary to control the
logic levels of the Clock signal both before and after each Clock
signal edge sent to the sequencer logic circuit, in order to main-
tain proper stepping operation.
Clock Edge Timing
With regard to the input logic of the CW/CCW, M1, M2, and M3
pins, a 1 s delay should occur both before and after the pulse
edges and as setup and hold times. The sequencer logic circuitry
might malfunction if the logic polarity is changed during these
setup and hold times. (Refer to figure 4).
Reset Release and Clock Input Timing
The Reset pulse width is equivalent to the high pulse level hold
time. It should be greater than the 2 s Clock input pulse width.
When the timing of a Reset release (falling edge) and a Clock
edge is simultaneous, the internal logic might cause an unex-
pected operation. Therefore, a greater than 5 s delay is required
between the falling edge of the Reset input and the next rising
edge of the Clock input. (Refer to figure 4).
Logic Level Change
Logic level inputs on CW/CCW, M1, M2, and M3 set the transla-
tor step direction (CW/CCW) and step mode (M1, M2, and M3;
refer to the Commutation Truth Table). Changes to these inputs
do not take effect until the rising edge of the Clock input. How-
ever, depending on the type and state of a motor, there may be
errors in motor operation. A thorough evaluation on the changes
of sequence should be carried out.
Figure 4. Input Signal Timing. When awakening from Sleep1 or Sleep2 mode, a delay of 100 s or
longer before sending a Clock pulse is recommended.
Reset 2 s(min)
2 s(min)
2 s(min)
2 s(min)
1 s(min) 1 s(min)
1 s(min) 1 s(min)
2 s(min)
5 s(min) 4 s(min)
Clock
CW/CCW
M1, M2, M3
14
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Figure 5. Full step; for microstep and full/half step products
Sequence Selection
Mode Pin Logic
M1 M2 M3
Full Step
8Low Low Low
Shows the state to which the stepping sequence progresses at the rising
(positive) edge of the Clock input.
A
B
B
A
012
70.7
0
70.7
0
RESET
CLOCK
CW
CCW
Stepping Sequence Diagrams
15
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Figure 6. Full step; for microstep and full/half step products
Sequence Selection
Mode Pin Logic
M1 M2 M3
Full Step
FHigh Low Low
4'5'6
%.1%-
##
B
%%9
$
%9
Shows the state to which the stepping sequence progresses at the rising
(positive) edge of the Clock input.
16
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Figure 7. Half step; for microstep and full/half step products
Sequence Selection
Mode Pin Logic
M1 M2 M3
Half Step
8, F Low High Low
A
B
B
A
01234
100
70.7
0
70.7
0
RESET
CLOCK
CW
CCW
Shows the state to which the stepping sequence progresses at the rising
(positive) edge of the Clock input.
17
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Figure 8. Half step; for microstep and full/half step products
Sequence Selection
Mode Pin Logic
M1 M2 M3
Half Step
FHigh High Low
A
B
B
A
01234
100
0
0
RESET
CLOCK
CW
CCW
Shows the state to which the stepping sequence progresses at the rising
(positive) edge of the Clock input.
18
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Figure 9. Quarter step; for microstep products
Sequence Selection
Mode Pin Logic
M1 M2 M3
Quarter
Step Low Low High
A
B
B
A
0123 4 56 7 ８
92 .4
100
70 .7
38 .2
0
70.7
38.2
0
92.4
RESET
CLOCK
CW
CCW
19
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Figure 10. Eighth step; for microstep products
Sequence Selection
Mode Pin Logic
M1 M2 M3
Eighth
Step High Low High
A
B
B
A
012345 6 7 891
0
1
1
1
2
1
3
1
4
1
5
1
6
98.1
92.4
100
98.1
83.1
70.7
55.5
38.2
19.5
0
83.1
70.7
55.5
38.2
19.5
0
92.4
RESET
CLOCK
CW
CCW
Shows the state to which the stepping sequence progresses at the rising
(positive) edge of the Clock input.
20
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Figure 11. Sixteenth step; for microstep products
Sequence Selection
Mode Pin Logic
M1 M2 M3
Sixteenth
Step Low High High
A
B
B
A
98.1
92.4 95.7
100
98.1 95 .7
88.2
83.1
77.3
70.7
63.4
55.5
47.1
38.2
29.0
19.5
9.8
0
88.2
83.1
77.3
70.7
63.4
55.5
47.1
38.2
29.0
19.5
9. 8
0
92.4
CW
CCW
1023465789
1
0
1
1
1
2
1
3
1
5
1
4
1
6
1
7
1
8
1
9
2
0
2
1
2
2
2
3
2
4
2
5
2
6
2
7
2
8
2
9
3
0
3
1
3
2
…
RESET
CLOCK
Shows the state to which the stepping sequence progresses at the rising
(positive) edge of the Clock input.
21
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Table 4. Excitation Mode States
Direction
Internal Sequence State Step Sequencing
Phase A Phase B Full Step Half Step 1/4 Step 1/8 Step 1/16 Step
PWM Mode PWM Mode Mode 8 Mode F Mode 8, F Mode F
Counter
Clockwise
Clockwise
A 8 B 8 X X* X X* X X X
A7B9 X
A6BA XX
A5BB X
A4BC XXX
A3BD X
A2BE XX
A1BF X
––BF XXXXX
A¯1BF X
A¯2BE XX
A¯3BD X
A¯4BC XXX
A¯5BB X
A¯6BA XX
A¯7B9 X
A¯8B8XX*XX*XXX
A¯9B7 X
A¯AB6 XX
A¯BB5 X
A¯CB4 XXX
A¯DB3 X
A¯EB2 XX
A¯FB1 X
A¯F–– XXXXX
A¯F B¯ 1 X
A¯E B¯ 2XX
A¯D B¯ 3 X
A¯C B¯ 4XXX
A¯B B¯ 5 X
A¯A B¯ 6XX
A¯9 B¯ 7 X
A¯8 B¯ 8XX*XX*XXX
A¯7 B¯ 9 X
A¯6 B¯ AXX
A¯5 B¯ B X
A¯4 B¯ CXXX
A¯3 B¯ D X
A¯2 B¯ EXX
A¯1 B¯ F X
––
B¯ F XXXXX
A1 B¯ F X
A2 B¯ EXX
A3 B¯ D X
A4 B¯ CXXX
A5 B¯ B X
A6 B¯ AXX
A7 B¯ 9 X
A8 B¯ 8XX*XX*XXX
A9 B¯ 7 X
AA
B¯ 6XX
AB B¯ 5 X
AC B¯ 4XXX
AD B¯ 3 X
AE B¯ 2XX
AF B¯ 1 X
AF–– XXXXX
AFB1 X
AEB2 XX
ADB 3 X
ACB 4 XXX
ABB5 X
AAB6 XX
A9B7 X
Sequence state is Mode 8, but step reference current ratio is Mode F. Mode F has step reference current ratio of 100%, and PWM off-time of 12 s.
Excitation Change Sequence
The change of excitation modes is determined by the settings of
the excitation pins (M1, M2, and M3) before and after the step
signal.Table 4 shows each excitation mode state setting.
22
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Individual Circuit Descriptions
Monolithic IC (MIC)
• Sequencer Logic The single Clock input is used for step tim-
ing. Direction is controlled by the CW/CCW input. Commutation
mode is controlled by the combination of the M1, M2, and M3
inputs logic levels. For details, refer to the Commutation Truth
Table.
• PWM Control Each pair of outputs is controlled by a fixed off-
time PWM current-control circuit. The internal oscillator (OSC)
sets the off-time. Its operation mechanism is identical to that of
the SLA7070M family. Refer to the PWM Current Control sec-
tion for further details.
• Synchronous Control This function prevents occasional
motor noise during Hold mode, which normally results from
asynchronous PWM operation of both motor phases. A logic
high at the Sync input sets synchronous operation. A logic low
sets 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 staircase
current. The use of synchronous operation when the motor is not
in operation is allowed only in full/half step sequence timing, due
to the difference in the current controlled and PWM off-time at
other step sequence timings.
• DAC (D-to-A Converter) In microstep sequencing, the cur-
rent at each step is set by the value of a sense resistor (RSInt), a
reference voltage (VREF), and the output voltage of the DACs,
controlled by the output of the sequencer / translator). Please refer
the electric characteristic, Step Reference Current Ratio, page 8.
• Regulator Circuit The integrated regulator circuit is used in
driving the output MOSFET gates and powering other internal
linear circuits.
• Protect Circuit A built-in protection circuit against motor coil
opens or shorts is provided. Protection is activated by sensing
voltage on the internal RSInt resistors; therefore, an overcurrent
condition cannot be detected which results from the the Outx pins
or Sensex pins, or both, shorting to Gnd. Protection against motor
coil opens is available only during PWM operation; therefore,
it does not work at constant voltage driving, when the motor is
rotating at high speed. Operation of the protection circuit disables
all of the DMOS outputs. To come out of protection mode, cycle
the logic supply, VDD
.
• TSD circuit This circuit protects a driver by shifting the output
to Disable mode when the temperature of a product control IC
(MIC) rises and becomes higher than threshold value. In order to
reset, cycle the logic supply, VDD
.
Output MOSFET Chip
The value of the built-in output DMOS chip varies according
to which of the four different output current ratings has been
selected.
Sense Resistor
The resistance varies according to which of the four different
output current ratings has been selected, as follows:
Output Current
(A)
RSInt Resistance
( typ)
1 0.305
1.5 0.305
2 0.205
3 0.155
Each resistance shown above includes the inherent resistance
(approximately 5 m) in the resistor itself.
23
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
PWM Current Control
Blanking Time
The actual operating waveforms on the Sensex pins when driving
a motor are shown in figure 12. The actual operating waveforms
on the Sensex pins when driving a motor are shown in figure 13.
Immediately after PWM turns OFF, ringing (or spike) noise on
the Sensex pins isobserved for a few s. Ringing noise can be
generated by various causes, such as capacitance between motor
coils and inappropriate motor wiring.
Each pair of outputs is controlled by a fixed off-time (7 to 12 s,
depending on stepping mode) PWM current-control circuit that
limits the load current to a target value, ITRIP . Initially, an output
is enabled and current flows through the motor winding and the
current-sense resistors. When the voltage across the current sense
resistor equals the DAC output voltage, VTRIP , the current sense
comparator resets the PWM latch. This turns off the driver for the
fixed off-time, during which the load inductance causes the cur-
rent to recirculate for the off-time period. Therefore, if the ringing
noise on the sense resistor equals and surpasses VTRIP , PWM
turns off.
To prevent this phenomenon, the blanking time is set to override
signals from the current-sense comparator for a certain period
immediately after PWM turns on.
Functional Description
ITRIP
5 s/div
ITRIP
500 ns/div
Figure 12. Operating waveforms on the Sensex pins during PWM chopping (circled area of left
panel is shown in expanded scale in right panel)
Figure 13. Sensex pin waveform during PWM control
t
ON
Blanking Time
A
A
0
I
TRIP
t
OFF
(Fixed)
PWM Pulse Width
24
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
• Blanking time and seeking phenomenon Although current
control can be improved by shortening blanking time, the degree
of margin to a ringing noise decreases simultaneously. For this
reason, when a motor is driven by the device, a seeking phenom-
enon may occur. Figure 14 shows an example of the waveform
when the phenomenon occurs.
• Blanking time difference The difference in blanking time is
shown in table 5. This comparison is based on the case where
drive conditions, such as a motor, motor power supply voltage,
and Ref input voltage, and a circuit constant were kept the same
while only the indicated parameter was changed.
Minimum PWM On-time ton(min)
. The product blanking time is
fixed by the PWM control. Thus, when the on-time is shortened
in order to reduce the current, it would not go below the blanking
time. Minimum PWM On-time refers to the time the output is
on during this blanking period, that is, when the output MOSFET
actually is turned on. In other words, the blanking time deter-
mines the minimum time (small in table 5).
Minimum coil current. This refers to the coil current when
PWM control is performed during PWM minimum on-time. In
other words, when the coil current is reduced when the power is
reduced, where blanking time is shorter can reduce current.
• Coil current waveform distortion during a high velocity
revolution While a microstep drive is active, the ITrip value
changes with the Clock input, to the predetermined value. The
Itrip value (internal reference voltage splitting ratio) is set up to be
a sine wave. Because PWM control of the motor coil current is
set according to the Itrip value, the coil current will be controlled
to be sine wave-like. In fact, according the inductance character-
istic of the coil, the device requires some time to bring the coil
current completely to the targeted value.
Roughly, the relationship between the convergence time (tconv)
between the Itrip value of the coil current and the duty cycle (tclk)
of the input Clock pulse in any mode is:
tconv < tclk (1)
where the coil current waveform amplitude serves as the limit
for Itrip .
When the current attempts to increase, the full limits of tconv are
determined by the damping time constant of power supply volt-
age and the coil used. When the current attempts to decrease, the
limits are determined by the power supply voltage, the damping
time constant, and the minimum on-time.
When the frequency of the input clock is raised, because tclk
becomes small, it is normal that the case will occur in which the
coil current cannot be raised to the Itrip value within a single clock
period. In this situation, the waveform amplitude of the coil cur-
rent degenerates from the sine wave, referred to as waveform dis-
tortion.
20 s/div
Figure 14. Example of a Sensex terminal waveform during hunching
phenomenon
Table 5. Characteristic Comparison by the
Difference in Blanking Time
Parameter Better Performance
Internal Blanking Time Setting Short Long
PWM minimum on-time Short
Maximize ringing noise suppression Large
Minimum coil current Small
Coil current waveform distortion at a
high rotation (mainly microstep) Large
25
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Figure 15 shows the compared result of the waveform distor-
tion by observing the waveform of various devices for which the
operating condition of power supply voltage, the current preset
value, the motor, and so forth are kept the same. As shown in the
places circled (blanking time) in the figure, while the amplitude
envelope of the Sensex pin waveform, which is the same as the
current waveform, in the 1.7 s case has become sine wave-like,
the blanking time in the 3.2 s case has degenerated from an ideal
sine wave.
The term Large in table 5 means that the wave distortion will be
less where the blanking time is longer, assuming the same drive
conditions, while the wave distortion will be larger where the
blanking time is shorter, if the Clock frequency is the same. In
addition, when such waveform distortion is confirmed, there is
uncertainty if the motor characteristic will be affected. Therefore,
please make a final judgment after evaluating very thoroughly.
500 s/di
v
SenseA
SenseB
1.5 typ(
Blanking Time: 1.5 s (typ)
Clock
Figure 15. Comparison of a Sense terminal waveform during high speed revolution
26
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
PWM Off-Time
The PWM off-time for the SLA7070MPRT series is controlled
at a fixed time by an internal oscillator. It also is switched in
three levels by current proportion (see the Electrical Character-
istics table). In addition, the SLA7070MPRT series provides a
function that decreases losses occurring when the PWM turns
off. This function dissipates back EMF stored in the motor coil
at MOSFET turn-on, as well as at PWM turn-on (synchronous
rectification operation).
Figure 16 shows the difference in back EMF generation
between the SLA7060M series and SLA7070MPRT series. The
SLA7060M series performs on–off operations using only the
MOSFET on the PWM-on side, but the SLA7070MPRT series
also performs on–off operations using only the MOSFET on
the PWM-off side. To prevent simultaneous switching of the
MOSFETs at synchronous rectification operation, the IC has a
dead time of approximately 0.5 s. During dead time, the back
EMF flows through the body diode of the MOSFET.
Figure 16. Synchronous rectification operation
SLA7060M Series SLA7070MPRT Series
V
BB
RSExt RSInt
V
S
V
S
V
S
FET Gate
Signal
FET Gate
Signal
V
g
Stepper Motor Stepper Motor
V
BB
I
off
I
on
I
off
I
on
V
S
V
g
V
g
V
g
V
g
V
g
PWM On PWM Off PWM On
Back EMF at Dead Time
V
g
+V
V
REF
0
t
V
g
+V
V
REF
0
0 0
t
t t
PWM On PWM Off PWM On
Dead
Time
Dead
Time
27
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Protection Functions
The SLA7070MPRT series includes a motor coil short-circuit
protection circuit, a motor coil open protection circuit, and an
overheating protection circuit. An explanation of each protection
circuit is provided below.
• Motor Coil Short-Circuit Protection (Load Short) Circuit.
This protection circuit, embedded in the SLA7070MPRT series,
begins to operate when the device detects an increase in the sense
resistor voltage level, VRS. The voltage at which motor coil short-
circuit protection starts its operation, VOCP , is set at approxi-
mately 0.7 V. The output is disabled at the time the protection
circuit starts, where VRS exceeds VOCP . (See figure 17.)
• Motor Coil Open Protection (Patent acquired) Driver destruc-
tion can occur when one output pin (motor coil) is disconnected
in a unipolar drive during operation. This is because a MOSFET
connected after disconnection will be in the avalanche break-
down state, where very high energy is added with back EMF
when PWM is off. With an avalanche state, an output cancels
the energy stored in the motor coil where the resisting pressure
between the drain and source of the MOSFET is reached (the
condition which caused the breakdown).
Although MOSFETs with a certain amount of avalanche energy
tolerance rating are used in the SLA7070MPRT series, avalanche
energy tolerance falls as temperature increases.
Because high energy is added repeatedly whenever PWM opera-
tion disconnects the MOSFET, the temperature of the MOSFET
rises, and when the applied energy exceeds the tolerance, the
driver will be destroyed. Therefore, a circuit which detects
this avalanche state and protects the driver was added in the
SLA7070MPRT series. The operation is shown in figure 18.
As explained above, when the motor coil is disconnected, the
accumulated voltage in the MOSFET causes a reverse current to
flow during the PWM off-time. For this reason, VRS that is nega-
tive during the PWM off-time in a normal operation becomes
positive when the motor coil is disconnected. Thus, a discon-
nected motor is detectable by sensing that VRS in the PWM off-
time is positive.
In the SLA7070MPRT series, in order to avoid detection mal-
functions, when a state of motor disconnection is detected 3 times
continuously, the protection functions are enabled (figure 19).
Note: When the breakdown of an output is confirmed by the
occurrence of surge noise after PWM turn-off, when a breakdown
condition continues after an overload disconnection undetected
time (topp) has elapsed, even if the load is not actually discon-
nected, a protection feature may operate. Please review the place-
ment of the motor, wiring, and so forth to improve and to settle
the breakdown time within the load disconnection undetected
time (topp) (application variations also must be taken into consid-
eration). When the breakdown is not confirmed, there will be no
issue in operation. Moreover, the device may be made to operate
normally by inserting a capacitor for surge noise suppression
between the Out and Gnd pins as one possible corrective strategy.
Stepper Motor
Coil Short Circuit
Coil Short Circuit
Normal Operation Output Disable
V
M
V
OCP
+V
V
REF
0
t
RSInt
V
S
V
S
V
g
Figure 17. Motor coil short circuit protection circuit operation. Overcurrent that flows without passing the sense resistor is undetectable.
To recover the circuit after protection operates, VDD must be cycled and started up again.
28
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
When the product temperature rises and exceeds Ttsdk , the protec-
tion circuit starts operating and all the outputs are set to Disable
mode.
Note: This product has multichip composition (one IC for control,
four MOSFETs, and two chip resistors). Although the loca-
tion which actually detects temperature is the control IC (MIC),
because the main heat sources are the MOSFET chips and the
chip resistors, which are separated by a distance from the control
IC, some delay will occur while the heat propagates to the control
IC. For this reason, because a rapid temperature change cannot
be detected, please perform worst-case thermal evaluations in the
application design phase.
Figure 18. Motor coil short circuit protection circuit operation. Overcurrent that flows without passing the sense resistor is undetectable.
To recover the circuit after protection operates, VDD must be cycled and started up again.
0
0
2VM
VREF
Vout
VRS
0
0
VM
VREF
Vout
VRS
VDSS
0 0
FET
Gate Signal Gate Signal
Breakdown (Avalanc
h
Vg
FET
Vg
Vg
SPM
PWM Operation
at Normal Device Operation PWM Operation
at Motor Disconnection
Disconnection
Motor
Disconnection
Motor
Disconnection
S
Vout
Vrs Rs
Vg
SPM
Vout
Vrs Rs
Ion
Ioff
VMVM
tOPP
tCONFIRM tCONFIRM tCONFIRM
tOPP tOPP
V
OUT
V
DSS
Figure 19. Coil Open Protection (Patent acquired)
A
0
A
Application Information
Motor Current Ratio Setting (R1, R2, RS)
The setting calculation of motor current, IOUT, for the
SLA7070MPRT series is determined by the ratios of the external
components R1, R2, and current sense resistor, RS. The following
is a formula for calculating IOUT:
when VREF is within specification. If VREF is set less than 0.1 V,
variation or impedance of the wiring pattern may influence the IC
and the possibility of less accurate current sensing becomes high.
The standard voltage for current ITrip that the SLA7070MPRT
series controls is partially divided by the internal DAC:
Lower Limit of Control Current
The SLA7070MPRT series uses a self-oscillating PWM current
control topology in which the off - time is fixed. As energy stored
in motor coil is eliminated within the fixed PWM of -time, coil
current flows intermittently, as shown in figure 20. Thus, average
current decreases and motor torque also decreases.
The point at which current starts flowing to the coil is considered
as the lower limit of the control current, IOUT(min), where IOUT is
the target current level. The lower limit of control current differs
by conditions of the motor or other factors, but it is calculated
from the following formula:
RDS(on) is the MOSFET on-resistance,
IO is the target current level,
Rm is the motor winding resistance,
Lm is the motor winding inductance,
tOFF is the PWM of -time, and
tC is calculated as:
where
Even if the control cur ent value is set at less than the lower limit of
the control current, there is no setting at which the IC fails to
operate. However, control current will worsen against setting
current.
Avalanche Energy
In the unipolar topology of the SLA7070MPRT series, a surge
voltage (ringing noise) that exceeds the MOSFET capacity to
withstand might be applied to the IC. To prevent damage, the
SLA7070MPRT series is designed with a built-in MOSFET hav-
ing sufficient avalanche resistance to withstand this surge volt-
age. Therefore, even if surge voltages occur, users will be able
to use the IC without any problems. However, in cases in which
the motor harness is long or the IC is used above its rated current
or voltage, there is a possibility that an avalanche energy could
be applied that exceeds Sanken design expectations. Thus, users
must test the avalanche energy applied to the IC under actual
application conditions.
The following procedure can be used to check the avalanche
energy in an application.
where
VM is the motor supply voltage,
ITRIP(Big)
ITRIP(Small)
Figure 20. Control current lower limit model waveform
SLA7070MPRT-AN, Rev. 1.4 SANKEN ELECTRIC CO., LTD
30
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Given:
From the waveform test result (reference figure 22)
VDS(AV) = 140 V,
ID = 1 A, and
t = 0.5 s.
The avalanche energy, EAV can be calculated using the following:
VDS(AV) ID
1/2
1/2
EAV =
=
=
t
140 (V)
0.035 (mJ)
1 (A) 0.5 10-6 (µs)
(7)
By comparing the EAV calculated with the graph shown in fig-
ure 23, the application can be evaluated if it is safe for the IC,
by being within the avalanche energy-tolerated does range of the
MOSFET.
On-Off Sequence of Power Supply (VBB and VDD)
There is no restriction of the on-off sequence between the main
power supply, VBB, and the logic supply, VDD.
0
4
8
12
16
20
0 25 50 75 100 125 150
EAV [mJ]
Product Temperature, Tc [°C]
SLA7073M and
SLA7078M
SLA7070M and
SLA7075M
SLA7071M and
SLA7076M
SLA7072M
and SLA7077M
Stepper Motor
RSInt
VM
ID
VDS(AV)
8
&5#8
+
&
V
Figure 21. Test points
Figure 22. Waveform at avalanche breakdown
Figure 23. SLA7070MPRT iterated avalanche energy tolerated level, EAV(max)
31
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Motor Supply Voltage (VM) and Main Power Supply
Voltage (VBB)
Because the SLA7070MPRT series has a structure that sepa-
rates the control IC (MIC) and the power MOSFETs as shown
in the Functional Block diagrams, the motor supply and main
power supply are separated. Therefore, it is possible to drive
the IC using different power supplies and different voltages for
motor supply and main power supply. However, extra caution is
required because the supply voltage ranges differ among power
supplies.
Internal Logic Circuits
Reset
The sequencer/translator circuit of this product is initialized after
logic supply (VDD) is applied, and the power-on reset function
operates. To initialize the sequencer/translator, the output imme-
diately after power-on indicates the status that the power circuits
are in the home state. In a case where the sequencer/translator
must be reset after the motor has been operating, a reset signal
must be input on the Reset pin. In a case in which external reset
control is not necessary, and the Reset pin is not used, the Reset
pin must be pulled to logic low on the application circuit board.
Clock Input
When the Clock input signal stops, excitation changes to the
motor Hold state. At this time, there is no difference to the IC if
the Clock input signal is at the low level or the high level. The
SLA7070MPRT series is designed to move one sequence incre-
ment at a time, according to the current stepping mode, when a
positive Clock pulse edge is detected.
Chopping Synchronous Circuit
The SLA7070MPRT series has a chopping synchronous func-
tion to protect from abnormal noises that may occasionally occur
during the motor Hold state. This function can be operated by
setting the Sync pin at high level. However, if this function is
used during motor rotation, control current does not stabilize, and
therefore this may cause reduction of motor torque or increased
vibration. So, Sanken does not recommend using this function
while the motor is rotating. In addition, the synchronous circuit
should be disabled in order to control motor current properly in
case it is used other than in dual excitation state (Modes 8 and F)
or single excitation Hold state.
In normal operation, generally the input signal for switching can
be sent from an external microcomputer. However, in applica-
tions where the input signal cannot be transmitted adequately due
to limitations of the port, the following method can be taken to
use the functions.
The schematic diagram in figure 24 shows how the IC is designed
so that the Sync signal can be determined by the Clock input
signal. When a logic high signal is received on the Clock pin,
the internal capacitor, C, is charged, and the Sync signal is set to
logic low level. However, if the Clock signal cannot rise above
logic low level (such as when the circuit between the microcom-
puter and the IC is not adequate), the capacitor is discharged by
the internal resistor, R, and the Sync signal is set to logic high,
causing the IC to shift to synchronous mode.
The RC time constant in the circuit should be determined by the
minimum clock frequency used. In the case of a sequence that
keeps the Clock input signal at logic high, an inverter circuit must
be added. In a case where the Clock signal is set at an undeter-
mined level, an edge detection circuit (figure 25) can be used to
prepare the signal for the Clock input, allowing correct process-
ing by the circuit shown in figure 24.
Output Disable (Sleep1 and Sleep2) Circuits
There are two methods to set this IC at motor free-state (coast,
with outputs disabled). One is to set the Ref/Sleep1 pin to more
than 2 V (Sleep1), and the other (Sleep2) is to set the excitation
signals (pins M1, M2, and M3). In either way, the IC will change
to Sleep mode, stopping the main power supply at the same time,
and decreasing circuit current. The difference between the two
methods is that, in the first way, the internal sequencer remains
in an enabled state, and in the latter method, the IC enters the
Clock Sync
VCC
74HC1474HC14
RC
Figure 24. Clock signal shutoff detection circuit
Figure 25. Clock signal edge detection circuit
Step
Clock Clock
32
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Hold state. Moreover, in the method using the excitation signals
(Sleep2), excitation timing remains in a standby state, even if a
signal is input on the Clock pin during Sleep mode.
When awaking to normal operating mode (motor rotation) from
Disable (Sleep1 or Sleep2) mode, set an appropriate delay time
from cancellation of the Disable mode to the initial Clock input
edge. In doing so, consider not only the rise time for the IC,
but also the rise time for the motor excitation current, which is
important (see figure 26).
Ref/Sleep1 Pin
The Ref/Sleep1 pin provides access to the following functions:
• Standard voltage setting for output current level setting
• Output Enable-Disable control input
These functions are further described in the Truth Table section,
and in the discussion of output disabling, above.
Range A. In this range, control current value also varies in
accordance with VREF. Therefore, losses in the IC and the sense
resistors must be given extra consideration.
Range B. In this range, the voltage that switches output enable
and disable (Sleep mode) exists. At enable, the same cautions
apply as in range A. In addition, for some cases, there are pos-
sibilities that the output status will become unstable as a result of
iteration between enable and disable.
Logic Input Pins
If a logic input pin (Clock, Reset, CW/CCW, M1, M2, M3, or
Sync) is not used (fixed logic level), the pin must be tied to VDD
or Gnd. Please do not leave them floating, because there is pos-
sibility of undefined effects on IC performance when they are
left open.
Output Pins (MO and Flag). The MO and Flag output pins are
designed as monitor outputs, and inside of the IC is an output
inverter (see figure 27). Therefore, let these pins float if they are
not used.
Thermal Design Information
It is not practical to calculate the power dissipation of the
SLA7070MPRT series accurately, because that would require
factors that are variable during operation, such as time periods
and excitation modes during motor rotation, input frequencies
and sequences, and so forth. Given this situation, it is preferable
to perform an approximate calculation at worst conditions. The
following is a simplified formula for calculation of power dis-
sipation:
(RDS(on)+ RS)I2
OUT 2
P
D=
(8)
where
P is the power dissipation in the IC,
IOUT is the operating output current,
RDS(on) is the resistance of the output MOSFET, and
RS is the current sense resistance.
Based on the PD calculated using the above formula, the
expected increase in operating junction temperature, TJ , of the
IC can be estimated using figure 28. This result must be added
to the worst case ambient temperature when operating, TA(max).
Based on the calculation, there is no problem unless TA(max) plus
TJ exceeds 150°C.
100 s
(minimum)
Ref/Sleep1 or
M1, M2, and M3
Clock
t
Figure 26. Timing delay between Disable mode cancellation and the next
Clock input
Figure 27. MO pin and Flag pin general internal circuit layout
Figure 28. Temperature increase
V
Mo or FLAG
DD
Static electricity
protection circuit
150
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
125
100
75
50
25
0
ΔTC-A = 21.3 x PD
ΔTJ-A = 26.6 x PD
Maximum Allowable Power Dissipation, P
D(max)
(W)
Increase in Junction Temperature
ΔT
J
(°C)
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SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
When the IC is used with a heatsink attached, device package
thermal resistance, RJA
, is a variable used in calculating Tj-a.
The value of RFIN is calculated from the following formula:
R
θJA≈RθJC+RθFin=RθJA–RθCA+RθFin
(9)
where Rj-a is the thermal resistance of the heatsink. Tj-a can be
calculated with using the value of RJA.
The following procedure should be used to measure product tem-
perature and to estimate junction temperature in actual operation:
First, measure the temperature rise at pin 12 of the device (Tc-a).
Second, estimate the loss (P) and junction temperature (Tj) from
the temperature rise with reference to figure 28, temperature
increase graph. At this point, the device temperature rise )(Tc-a)
and the junction temperature rise (Tj) are almost equivalent under
the following formula:
ΔT
J ΔT
c-a+P
DRθj-c
≈
(10)
CAUTION
The SLA7070MPRT series is designed as a multichip, with
separate power elements (MOSFET), control IC (MIC), and
sense resistance. Consequently, because the control IC cannot
accurately detect the temperature of the power elements (which
are the primary sources of heat), the ICs do not provide a protec-
tion function against overheating. For thermal protection, users
must conduct sufficient thermal evaluations to be able to ensure
that the junction temperature does not exceed the warranty level
(150°C).
This thermal design information is provided for preliminary
design estimations only. The thermal performance of the IC will
be significantly determined by the conditions of the application,
in particular the state of the mounting PCB, heatsink, and the
ambient air. Before operating the IC in an application, the user
must experimentally determine the actual thermal performance.
The maximum recommended case temperatures (at the center, pin
12) for the IC are:
• With no external heatsink connection: 90°C
• With external heatsink connection: 80°
34
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
Output MOSFET On-Voltage, VDS(on)
SLA7070MPRT/SLA7075MPRT
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
-25 0 25 50 75 100 125
VDS(on) (V)
Io=1
A
Io=0.5A
SLA7071MPRT/SLA7076MPRT
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
-25 0 25 50 75 100 125
Io=1
A
Io=1.5A
SLA7072MPRT/SLA7077MPRT
Product Temperature, TC (°C) Product Temperature, TC (°C)
Product Temperature, TC (°C)Product Temperature, TC (°C)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
-25 0 25 50 75 100 125
Io=1
A
Io=2
A
SLA7073MPRT/SLA7078MPRT
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
-25 0 25 50 75 100 125
Io=1
A
Io=3
A
Io=2
A
Product Temperature, TC (°C)
VDS(on) (V)
VDS(on) (V)
VDS(on) (V)
Characteristic Data
35
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
SLA7070MPRT/SLA7075MPRT
0.6
0.7
0.8
0.9
1.0
1.1
-25 0 25 50 75 100 125
V
f
(V)
Io=1
A
Io=0.5A
SLA7071MPRT/SLA7076MPRT
0.6
0.7
0.8
0.9
1.0
1.1
-25 0 25 50 75 100 125
Io=1
A
Io=1.5A
0.6
0.7
0.8
0.9
1.0
1.1
-25 0 25 50 75 100 125
SLA7072MPRT/SLA7077MPRT
Io=1A
Io=2A
0.6
0.7
0.8
0.9
1.0
1.1
-25 0 25 50 75 100 125
SLA7073MPRT/SLA7078MPRT
Io=1A
Io=2A
Io=3A
Product Temperature, T
C
(°C) Product Temperature, T
C
(°C)
Product Temperature, T
C
(°C) Product Temperature, T
C
(°C)
V
f
(V)
V
f
(V)
V
f
(V)
Output MOSFET Body Diode Forward Voltage, Vf
36
SANKEN ELECTRIC CO., LTD.
SLA7070MPRT-AN, Rev. 1.4
• The contents in this document are subject to changes, for improvement and other purposes, without notice. Make sure that this is the
latest revision of the document before use.
• Application and operation examples described in this document are quoted for the sole purpose of reference for the use of the prod-
ucts herein and Sanken can assume no responsibility for any infringement of industrial property rights, intellectual property rights or
any other rights of Sanken or any third party which may result from its use.
• Although Sanken undertakes to enhance the quality and reliability of its products, the occurrence of failure and defect of semicon-
ductor 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 the society due to device
failure or malfunction.
• Sanken products listed in this document are designed and intended for the use as components in general purpose electronic equip-
ment or apparatus (home appliances, office equipment, telecommunication equipment, measuring equipment, etc.).
When considering the use of Sanken products in the applications where higher reliability is required (transportation equipment and
its control systems, traffic signal control systems or equipment, fire/crime alarm systems, various safety devices, etc.), and whenever
long life expectancy is required even in general purpose electronic equipment or apparatus, please contact your nearest Sanken sales
representative to discuss, prior to the use of the products herein.
The use of Sanken products without the written consent of Sanken in the applications where extremely high reliability is required
(aerospace equipment, nuclear power control systems, life support systems, etc.) is strictly prohibited.
• In the case that you use Sanken products or design your products by using Sanken products, the reliability largely depends on the
degree of derating to be made to the rated values. Derating may be interpreted as a case that an operation range is set by derating the
load from each rated value or surge voltage or noise is considered for derating in order to assure or improve the reliability. In general,
derating factors include electric stresses such as electric voltage, electric current, electric power etc., environmental stresses such
as ambient temperature, humidity etc. and thermal stress caused due to self-heating of semiconductor products. For these stresses,
instantaneous values, maximum values and minimum values must be taken into consideration.
In addition, it should be noted that since power devices or IC's including power devices have large self-heating value, the degree of
derating of junction temperature affects the reliability significantly.
• When using the products specified herein by either (i) combining other products or materials therewith or (ii) physically, chemically
or otherwise processing or treating the products, please duly consider all possible risks that may result from all such uses in advance
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