HIGH-CURRENT PWM, UNIPOLAR STEPPER MOTOR CONTROLLER/DRIVERS The SLA7024M, SLA7026M, and SMA7029M are designed for high-efficiency and high-performance operation of 2-phase, unipolar stepper motors. An automated, innovative packaging technology combined with power FETs and monolithic logic/control circuitry advances power multi-chip modules (PMCMs™) toward the complete integration of motion control. Highly automated manufacturing techniques provide low-cost and exceptionally reliable PMCMs suitable for controlling and directly driving a broad range of 2-phase, unipolar stepper motors. The three stepper motor multi-chip modules differ primarily in output current ratings (1.5 A or 3.0 A) and package style. SMA7029M 1 OFF DELAY A 2 3 GROUND A 4 IN A 5 VREF + OUT A 6 SENSE A 7 8 SENSE B 9 OUT B 10 OFF DELAY B 11 GROUND B 12 REFERENCE B 13 IN B 14 OUT B 15 All three PMCMs are rated for an absolute maximum limit of 46 V and utilize advanced NMOS FETs for the high-current, high-voltage driver outputs. The avalanche-rated (≥100 V) FETs provide excellent ON resistance, improved body diodes, and very-fast switching. The multi-chip ratings and performance afford significant benefits and advantages for stepper drives when compared to the higher dissipation and slower switching speeds associated with bipolar transistors. Normally, heat sinks are not required for the SLA7024M or SMA7029M. The SLA7026M, in demanding, higher-current systems designs, necessitates suitable heat transfer methods for reliable operation. VCC VREF CONTROL/LOGIC CNTRL SPLY + REFERENCE A CONTROL/LOGIC OUTA Dwg. PK-007 Complete applications information is given on the following pages. PWM current is regulated by appropriately choosing current-sensing resistors, a voltage reference, a voltage divider, and RC timing networks. The RC components limit the OFF interval and control current decay. Inputs are compatible with 5 V logic and microprocessors. ABSOLUTE MAXIMUM RATINGS at TA = +25°C Load Supply Voltage, VBB . . . . . . . . . . . . 46 V FET Output Voltage, VDS . . . . . . . . . . . 100 V Control Supply Voltage, VCC . . . . . . . . . . 46 V Peak Output Current, IOUTM (tw ≤ 100 µs) SLA7024M . . . . . . . . . . . . . . . . . . . . . 3.0 A SLA7026M . . . . . . . . . . . . . . . . . . . . . 5.0 A SMA7029M . . . . . . . . . . . . . . . . . . . . 3.0 A Continuous Output Current, IOUT SLA7024M . . . . . . . . . . . . . . . . . . . . . 1.5 A SLA7026M . . . . . . . . . . . . . . . . . . . . . 3.0 A SMA7029M . . . . . . . . . . . . . . . . . . . . 1.5 A Input Voltage Range, VIN . . . . -0.3 V to 7.0 V Reference Voltage, VREF . . . . . . . . . . . 2.0 V Package Power Dissipation, PD . See Graph Junction Temperature, TJ . . . . . . . . . +150°C Operating Temperature Range, TA . . . . . . . . . . . . . . . . . . . . -20°C to +85°C Storage Temperature Range, Tstg . . . . . . . . . . . . . . . . . . -40°C to +150°C BENEFITS AND FEATURES ■ ■ ■ ■ ■ ■ ■ ■ Cost-Effective, Multi-Chip Solution ‘Turn-Key’ Motion-Control Module Motor Operation to 3 A and 46 V 3rd Generation High-Voltage FETs 100 V, Avalanche-Rated NMOS Low r DS(on) NMOS Outputs Advanced, Improved Body Diodes Single-Supply Motor/Module Operation ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Half- or Full-Step Unipolar Drive High-Efficiency, High-Speed PWM Dual PWM Current Control (2-Phase) Programmable PWM Current Control Low Component Count PWM Drive Low Internal Power Dissipation Heat Sinking (Normally) Unnecessary Electrically Isolated Power Tab Logic IC- and µP-Compatible Inputs Machine-Insertable Package Always order by complete part number: Part Number Package Output Current SLA7024M 18-Lead Power-Tab SIP 1.5 A SLA7026M 18-Lead Power-Tab SIP 3.0 A SMA7029M 15-Lead SIP 1.5 A ™ Data Sheet 28201 SLA7024M, SLA7026M, AND SMA7029M SLA7024M, SLA7026M, AND SMA7029M HIGH-CURRENT PWM, UNIPOLAR STEPPER MOTOR CONTROLLER/DRIVERS SLA7024M and SLA7026M FUNCTIONAL BLOCK DIAGRAM CONTROL SUPPLY IN 7 12 V A/B IN A/B OUT A/B OUT 6 5 8 1 17 16 18 11 A/B CC REFERENCE REG. + 3 14 + 13 15 2 4 OFF-TIME DELAY 10 9 GROUND SENSE CHANNEL A PIN NUMBERS CHANNEL B PIN NUMBERS Dwg. FK-005 Note that channels A and B are electrically isolated. SMA7029M FUNCTIONAL BLOCK DIAGRAM CONTROL SUPPLY IN A/B OUT A/B 8 5 1 6 8 14 10 15 OUT A/B V CC REFERENCE REG. + 3 13 + 11 12 2 4 OFF-TIME DELAY GROUND 9 7 CHANNEL A PIN NUMBERS CHANNEL B PIN NUMBERS SENSE Dwg. FK-005-1 Note that except for the control supply, channels A and B are electrically isolated. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright © 1994 Allegro MicroSystems, Inc. ™ SLA7024M, SLA7026M, AND SMA7029M HIGH-CURRENT PWM, UNIPOLAR STEPPER MOTOR CONTROLLER/DRIVERS SLA7024M and SLA7026M 25 20 PREFIX 'SLA' R θJM = 5.0°C/W 15 CONTROL/LOGIC CONTROL/LOGIC PREFIX 'SMA' RθJM = 6.0°C/W VCC VCC VREF 10 VREF + + REFERENCE B 15 16 17 18 OUT B 14 IN B 13 IN B 12 GROUND B 11 OFF DELAY B Dwg. GK-018 10 CNTRL SPLY B 9 OUTB 8 SENSE B 7 SENSE A 150 6 OUT A 125 5 CNTRL SPLY A 75 100 TEMPERATURE in °C 4 IN A 50 3 IN A 25 2 GROUND A 0 1 REFERENCE A PREFIX 'SMA' R θJA = 31°C/W OFF DELAY A PREFIX 'SLA' R θJA = 28°C/W 5 OUTA ALLOWABLE PACKAGE POWER DISSIPATION in WATTS ALLOWABLE PACKAGE POWER DISSIPATION Dwg. PK-006 ELECTRICAL CHARACTERISTICS at TA = +25°C Limits Characteristic FET Leakage Current FET ON Voltage FET ON Resistance Body Diode Symbol IDSS VDS(ON) rDS(on) VSD Forward Voltage Test Conditions Min Typ Max Units VDS = 100 V, VCC = 44 V — — 4.0 mA (SLA7024M & SMA7029M) VCC = 14 V, IOUT = 1 A — — 600 mV (SLA7026M) VCC = 14 V, IOUT = 3 A — — 850 mV (SLA7024M & SMA7029M) VCC = 14 V, IOUT = 1 A — — 600 mΩ (SLA7026M) VCC = 14 V, IOUT = 3 A — — 285 mΩ (SLA7024M & SMA7029M) IOUT = –1 A — 0.9 1.5 V (SLA7026M) IOUT = –3 A — 0.9 1.6 V Control Supply Voltage VCC Operating 10 24 44 V Control Supply Current ICC VCC = 44 V — 10 15 mA IIN(H) VCC = 44 V, VIN = 2.4 V — — 40 µA IIN(L) VIN = 0.4 V — — -800 µA VIN(H) 2.0 — — V VIN(L) — — 0.8 V Input Current Input Voltage NOTE: Negative current is defined as coming out of (sourcing) the specified device pin. SLA7024M, SLA7026M, AND SMA7029M HIGH-CURRENT PWM, UNIPOLAR STEPPER MOTOR CONTROLLER/DRIVERS TYPICAL STEPPER MOTOR APPLICATIONS (Half of Each Device Shown) SLA7024M and SLA7026M V BB A IN B IN B A OUT B 12 17 16 OUT B 18 11 VCC REG. R 1 510 Ω V b +5 V TO CHANNEL A VREF R 2 100 Ω 14 + + 2.4 kΩ R 5 td SENSE 13 15 10 +5 V 47 kΩ R3 C 3 2200 pF 470 pF C1 R S ≤1 Ω Dwg. EK-008 TRUTH TABLES (Device Types as Designated) WAVE DRIVE (FULL STEP) for SLA7024M and SLA7026M Sequence Input A Input A Input B Input B Output ON 0 H L L L A 1 L L H L B 2-PHASE (FULL STEP) OPERATION for SLA7024M and SLA7026M 2 L H L L A 3 L L L H B 0 H L L L A Sequence Input A Input A Input B Input B Outputs ON 0 H L H L AB 1 L H H L AB 2 L H L H AB 3 H L L H AB 0 H L H L AB HALF-STEP OPERATION (2-1-2 SEQUENCE) for SLA7024M, SLA7026M, and SMA7029M Sequence Input A Input A or tdA* Input B Input B or tdB* 0 H L L L 1 H L H L 2 L L H L 3 L H H L 4 L H L L 5 L H L H 6 L L L H 7 H L L H 0 H L L L Output(s) ON A AB B AB A AB B AB A *Logic signals to external open-collector inverter connected to tdA and tdB. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 ™ SLA7024M, SLA7026M, AND SMA7029M HIGH-CURRENT PWM, UNIPOLAR STEPPER MOTOR CONTROLLER/DRIVERS TYPICAL STEPPER MOTOR APPLICATIONS (Half of Device Shown) SMA7029M V BB A IN B A OUT B 8 14 V OUT B 10 15 CC REG. R 1 510 Ω V b +5 V TO CHANNEL A VREF R 2 100 Ω 13 + + 2.4 kΩ R 5 td SENSE 11 12 9 C1 470 pF +5 V R 3 47 kΩ C 3 2200 pF R S ≤1 Ω OPEN-COLLECTOR INVERTER Dwg. EK-008-1 TRUTH TABLES (SMA7029M Only) WAVE DRIVE (FULL STEP) for SMA7029M Sequence Input A Input tdA* Input B Input tdB* Output ON 0 H L L L A 1 L L H L B 2 L H L L A 3 L L L H B 0 H L L L A *Logic signals to external open-collector inverter connected to tdA and tdB. 2- PHASE (FULL STEP) OPERATION for SMA7029M Sequence Input A Input B Outputs ON 0 H L AB 1 H H AB 2 L H AB 3 L L AB 0 H L AB SLA7024M, SLA7026M, AND SMA7029M HIGH-CURRENT PWM, UNIPOLAR STEPPER MOTOR CONTROLLER/DRIVERS APPLICATIONS INFORMATION REGULATING THE PWM OUTPUT CURRENT The output current (and motor coil current) waveform is illustrated in Figure 1. Setting the PWM current trip point requires various external components: Vb = Reference supply (typically 5 V) R1, R2 = Voltage-divider resistors in the reference supply circuit RS = Current sensing resistor(s) NOTE: The maximum allowable VREF input voltage is 2.0 V. The voltage-divider must be selected accordingly. Normal PWM (Full-Current/Running) Mode IOUT is set to meet the specified running current for the motor (Figure 2) and is determined by: VREF IOUT ≈ (1) RS or, if VREF is not known IOUT ≈ R2 R1 + R2 • Vb (2) RS I OUT PHASE A 0 PHASE A Dwg. WK-001 FIGURE 1. PHASE A COIL CURRENT WAVEFORM Vb VCC INPUT V BB B R3 R1 B R5 R2 C1 td A V REF PEAK CURRENT DETECTOR PWM OFF-TIME CONTROL CONTROL LOGIC C3 A CURRENT CONTROL & RECIRCULATING CURRENT CONTROL SENSE RS Dwg. EK-009 FIGURE 2. PWM CONTROL (RUN MODE) 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 ™ SLA7024M, SLA7026M, AND SMA7029M HIGH-CURRENT PWM, UNIPOLAR STEPPER MOTOR CONTROLLER/DRIVERS For given values of R1, R2, and V b (VREF ≈ 0.82 V), Figure 3 illustrates output current as a function of current-sensing resistance (RS). OUTPUT TRIP CURRENT in AMPERES 3.0 SLA7026M MAX. 2.5 R1 = 510 Ω R2 = 100 Ω RX = ∞ 2.0 Vb = 5 V 1.5 1.0 SLA7024M & SMA7029M MAX. 0.5 0 0 0.5 1.0 1.5 2.0 2.5 3.0 CURRENT-SENSING RESISTANCE in OHMS 3.5 4.0 Dwg. GK-014 FIGURE 3. CURRENT-SENSING RESISTANCE Reduced/Holding Current Mode Additional circuitry (Figure 4) enables reducing motor current. The external transistor changes the voltage-divider ratio, VREF, and reduces the output current. IHOLD is determined by resistors R2 and RX in parallel: IHOLD ≈ or IHOLD ≈ R2 RX R1 R2 + R1 RX + R2 RX R2’ R1 + R2’ • • Vb (3) RS Vb (4) RS where R2’ = the equivalent value of R 2 and RX in parallel. Vb R1 RX R5 V REF HOLD SENSE R2 C3 RS Dwg. EK-010 FIGURE 4. HOLD CURRENT MODE SLA7024M, SLA7026M, AND SMA7029M HIGH-CURRENT PWM, UNIPOLAR STEPPER MOTOR CONTROLLER/DRIVERS For given values of R1, R2, and V b (VREF ≈ 0.82 V), Figures 5A and 5B illustrate output holding current as a function of RX for two values of currentsensing resistance (RS). 1.0 OUTPUT TRIP CURRENT in AMPERES RS = 0.8 Ω 0.8 RS = 1.0 Ω 0.6 0.4 R1 = 510 Ω R2 = 100 Ω Vb = 5 V 0.2 0 0 100 200 300 400 500 HOLDING-CURRENT RESISTANCE in OHMS 600 Dwg. GK-015 FIGURE 5A. HOLD-CURRENT RESISTANCE (SLA7024M and SMA7029M) 3.0 R1 = 510 Ω R2 = 100 Ω 2.5 OUTPUT TRIP CURRENT in AMPERES Vb = 5 V RS = 0.33 Ω 2.0 RS = 0.47 Ω 1.5 1.0 0.5 0 0 100 200 300 400 500 600 700 800 HOLDING-CURRENT RESISTANCE in OHMS Dwg. GK-015-1 FIGURE 5B. HOLD-CURRENT RESISTANCE (SLA7026M) NOTE: Holding current determines holding torque, which is normally greater than running torque. Consult motor manufacturer for recommended safe holding current and motor winding temperature limits in “standstill” or “detent” mode. The MOSFET outputs create ringing noise with PWM, but the RC filter precludes malfunctions. The comparator operation is affected by R5 and C3 and, thus, current overshoot is influenced by component values. Empirical adjustment to “fine-tune” the current limit is likely. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 ™ SLA7024M, SLA7026M, AND SMA7029M HIGH-CURRENT PWM, UNIPOLAR STEPPER MOTOR CONTROLLER/DRIVERS DETERMINING THE MOTOR PWM FREQUENCY The modules function asynchronously, with PWM OFF time fixed by R3 and C1 at input td. The OFF time can be calculated as: 2 tOFF ≈ -R3 • C1 • logn (1 - ) (5) Vb Recommended circuit constants and tOFF are: Vb = 5 V R3 = 47 kΩ C1 = 470 pF tOFF = 12 µs 40 ON TIME in µs RS = 1 Ω L/R = 1 to 3 ms 20 VCC = 24 V 30 25 30 20 VCC = 36 V 35 40 10 CHOPPING FREQUENCY in kHz 50 0 0 2 6 10 4 8 MOTOR RESISTANCE in OHMS 14 12 Dwg. GK-016 FIGURE 7. PWM FREQUENCY vs MOTOR RESISTANCE POWER DISSIPATION CALCULATIONS Excepting high-current applications utilizing the SLA7026M above approximately 2.0 A at +65°C (with 2-phase operation), the need for heat sinks is rare. The basic constituents of conduction losses (internal power dissipation) include: (a) FET output power dissipation (IOUT2 • rDS(on) or IOUT • VDS(ON)), (b) FET body diode power dissipation (VSD • IOUT), and (c) control circuit power dissipation (VCC • ICC ). Device conduction losses are calculated based on the operating mode (wave drive, half-step, or 2-phase). Assuming a 50% output duty cycle: Wave Drive = 0.5 (IOUT2 • rDS(on)) + 0.5 (VSD • IOUT) + (VCC • 15 mA) Half-Step = 0.75 (IOUT2 • rDS(on)) + 0.75 (VSD • IOUT) + (VCC • 15 mA) 2-Phase = (IOUT 2 • rDS(on)) + (VSD • IOUT ) + (VCC • 15 mA) SLA7024M, SLA7026M, AND SMA7029M HIGH-CURRENT PWM, UNIPOLAR STEPPER MOTOR CONTROLLER/DRIVERS PACKAGE RATINGS/DERATING FACTORS Thermal ratings/deratings for the multi-chip module packages vary slightly. Normally, the SLA7024M and SMA7029M do not need heat sinking when operated within maximum specified output current (≤1.0 A with 2-phase drive) unless the design ambient temperature also exceeds +60°C. Thermal calculations must also consider the temperature effects on the output FET ON resistance. The applicable thermal ratings for the PMCM packages are: SLA7024M and SLA7026M 18-Lead Power-Tab SIP RΘJA = 28°C/W (no heat sink) or 4.5 W at +25°C and a derating factor of -36 mW/°C for operation above +25°C. RΘJC = 5°C/W. SMA7029M 15-Lead SIP RΘJA = 31°C/W (no heat sink) or 4.0 W at +25°C and a derating factor of -32 mW/°C for operation above +25°C. RΘJC = 6°C/W. TEMPERATURE EFFECTS ON FET r DS(on) Analyzing safe, reliable operation includes a concern for the relationship of NMOS ON resistance to junction temperature. Device package power calculations must include the increase in ON resistance (producing higher output ON voltages) caused by higher operating junction temperatures. Figure 8 provides a normalized ON resistance curve, and all thermal calculations should consider increases from the given +25°C limits, which may be caused by internal heating during normal operation. NORMALIZED FET ON RESISTANCE 2.5 2.0 1.5 1.0 0.5 0 -40 0 +40 +80 JUNCTION TEMPERATURE in °C +120 +160 Dwg. GK-017 FIGURE 8. NORMALIZED ON RESISTANCE vs TEMPERATURE 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 ™ SLA7024M, SLA7026M, AND SMA7029M HIGH-CURRENT PWM, UNIPOLAR STEPPER MOTOR CONTROLLER/DRIVERS SLA7024M and SLA7026M Dimensions in Inches (for reference only) 0.126 ±0.006 x 0.150 1.22 ±0.008 0.126 ±0.006 0.961 ±0.008 ø 0.189 ±0.008 0.646 0.067 0.512 ±0.008 0.390 ±0.008 0.630 ±0.004 ±0.008 ±0.008 0.096 ±0.008 0.264 ±0.020 0.118 1 18 1.232 ±0.008 +0.008 0.026 –0.004 +0.008 0.022 –0.004 0.157 0.066 ±0.028 ±0.016 Dwg. MK-002-18 in Dimensions in Millimeters (controlling dimensions) 3.2 ±0.15 x 3.8 31±0.2 3.2 ±0.15 24.4 ±0.2 ø 4.8 ±0.2 16.4 ±0.2 1.7 13 ±0.2 9.9 ±0.2 16 ±0.2 ±0.1 2.45 ±0.2 6.7 ±0.5 3.0 1 18 0.55 +0.2 –0.1 31.3 ±0.2 +0.2 0.65 –0.1 1.68 ±0.4 4.0 ±0.7 Dwg. MK-002-18 mm NOTES: 1. Exact body and lead configuration at vendor’s option within limits shown. 2. Recommended mounting hardware torque: 4.34 – 5.79 lbf•ft (6 – 8 kgf•cm or 0.588 – 0.784 Nm). 3. The hatched area is exposed (electrically isolated) heat spreader. 4. Recommend use of metal-oxide-filled, alkyl-degenerated oil base, silicone grease (Dow Corning 340 or equivalent). SLA7024M, SLA7026M, AND SMA7029M HIGH-CURRENT PWM, UNIPOLAR STEPPER MOTOR CONTROLLER/DRIVERS SMA7029M Dimensions in Inches (for reference only) 1.24 MAX. 0.157 ±0.008 0.098 0.335 MAX. ±0.008 ±0.008 0.402 1.22 ±0.008 30° 0.057 ±0.006 0.264 ±0.020 0.118 1 0.022 +0.008 –0.004 15 +0.008 0.026 –0.004 0.157 0.080 ±0.028 ±0.004 Dwg. MK-005-15 in Dimensions in Millimeters (controlling dimensions) 31.5 MAX. 4.0 ±0.2 2.5 8.5 MAX. ±0.2 ±0.2 10.2 31±0.2 30° 1.45 ±0.15 6.7 ±0.5 3.0 1 15 +0.2 0.65 –0.1 0.55 +0.2 –0.1 2.03 ±0.1 4.0 ±0.7 Dwg. MK-005-15 mm NOTE: Exact body and lead configuration at vendor’s option within limits shown. The products described here are manufactured in Japan by Sanken Electric Co., Ltd. for sale by Allegro MicroSystems, Inc. Sanken Electric Co., Ltd. and Allegro MicroSystems, Inc. reserve the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the design of their products. The information included herein is believed to be accurate and reliable. However, Sanken Electric Co., Ltd. and Allegro MicroSystems, Inc. assume no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 ™