Unipolar 2-Phase Stepper Motor Driver ICs SLA7080MS Series Datasheet June, 2016 Rev.1.7 This document describes the SLA7080MS series, which are unipolar 2-phase stepping motor driver ICs. This document contains preliminary information on the products under development. If you have any questions, including information on options, please contact your nearest sales or representative office. Table of Contents 1. General Description .............................................................................. 2 2. Features and Benefits ........................................................................... 2 3. Part Numbers and Rated Currents ...................................................... 2 4. Specifications ......................................................................................... 3 5. Power Derating Chart ........................................................................... 5 6. Package Outline Drawing ..................................................................... 6 7. Functional Block Diagram and Pin Assignment ................................. 7 8. Application Example ............................................................................. 8 9. Truth Tables ........................................................................................... 9 10. Individual Circuit Descriptions .......................................................... 10 11. Functional Descriptions ...................................................................... 12 12. Application Information ...................................................................... 18 13. Thermal Design Information .............................................................. 22 14. Characteristics Data ........................................................................... 24 Important Notes.......................................................................................... 25 Sanken Electric Co., Ltd. http://www.sanken-ele.co.jp/en/ 1 / 26 SLA7080MS Series Datasheet Rev.1.7 1. General Description Thank you for your long years of patronage for each series of our unipolar 2-phase stepping motor driver ICs. The SLA7080MS series is our latest release. This document describes summaries of our latest products. 2. Features and Benefits (1) Main power supply voltages, VBB: 46 V (max.), 10 to 44 V normal operating range (2) Logic supply voltages, VDD: 3.0 to 5.5 V (3) Maximum output currents, IO(max): 2.0 A, 3.0 A (4) Stepping control for phase input (full-/half-stepping) (5) Built-in “sense resistor” detects motor current (6) All variants are pin-compatible for enhanced design flexibility (7) ZIP type 23-pin molded package (SLA package) (8) Self-exciting PWM current control with fixed OFF-time (9) Built-in synchronous rectifying circuit reduces power dissipation at PWM-OFF (10) Synchronous PWM chopping function prevents motor noise in the Hold mode (11) The Sleep mode to reduce IC input current in stand-by state (12) Built-in protection circuitry against motor coil opens/shorts and thermal shutdown protection (13) Externally-adjustable blanking times (Minimum ON-time): 3.2 µs, 5.2 µs 3. Part Numbers and Rated Currents Table 3-1 shows each part number and its rated current for the SLA7080MS series. Table 3-1. Part Numbers and Rated Currents Rated Current Part Number (Maximum Setting Value) SLA7082MS 2.0 A SLA7083MS 3.0 A Sanken Electric Co., Ltd. 2 / 26 SLA7080MS Series Datasheet Rev.1.7 4. Specifications Table 4-1. Absolute Maximum Ratings Unless specifically noted, TA = 25 °C Characteristic Symbol Rating Unit Load (Motor Supply Voltage) VM 46 V Main Power Supply Voltage VBB 46 V Logic Supply Voltage VDD 6 V Power supply to DC 7 V ≤1 μs (5% duty) 2.0 A SLA7082MS 3.0 A SLA7083MS Output Current IO 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 Allowable Power Dissipation PD 4.7 W Junction Temperature TJ 150 °C Operating Ambient Temperature TA −20 to 85 °C Storage Temperature Tstg −30 to 150 °C Remarks Control current value Without heatsink NOTE: Output current ratings may be limited by duty cycles, ambient temperatures, and heat sinking conditions. Do not exceed the maximum output current and maximum junction temperature (TJ) given above, under any conditions of use. Table 4-2. Recommended Operating Conditions Unless specifically noted, TA = 25 °C Characteristic Symbol Load (Motor Supply Voltage) VM Main Power Supply Voltage VBB Logic Supply Voltage VDD Standard Value Min. Max. 10 3.0 Unit 44 V 44 V 5.5 V Remarks Surge voltage at VDD pin should be less than ±0.5 V to avoid malfunctioning in operation Measured at Pin 12 (lead portion), without heatsink NOTE: As the motor supply voltage, VM, becomes higher, it also approaches the breakdown voltage of the OUTx pins (100 V min.); and breakdown will be more likely to happen. Even if one of the OUTx pins breaks down (due to surge noise or other factors), the SLA7080MS series will recognize it as abnormality (coil open) and will run appropriate protection functions. Therefore, a thorough evaluation is recommended. Case Temperature TC 90 °C Sanken Electric Co., Ltd. 3 / 26 SLA7080MS Series Datasheet Rev.1.7 Table 4-3. Electrical Characteristics Unless specifically noted, TA = 25 °C, VBB = 24 V, VDD = 5 V Characteristic Logic Supply Current MOSFET Breakdown Voltage Symbol IBB IBBS IDD VDSS MOS FET ON-Resistance RDS(on) Main Power Supply Current MOS FET Body Diode Forward Voltage Maximum Response Frequency Logic Input Voltage Logic Input Current REF Input Voltage fclk IIL IIH Overcurrent Detection Voltage3) Overcurrent Detection Current (VOCP / Rs) Load Disconnection Undetected Time Overheat Protection Temperature FLAG Output Voltage RS ton(min) VOCP 0.04 0.04 2.0 V VBB = 44 V, ID = 1 mA IO = 2.0 A IO = 3.0 A IO = 2.0 A IO = 3.0 A Clock duty cycle = 50% V µA µA 0.4 0.45 VDD ±10 VREF VREF − 0.03 0.199 0.205 0.150 0.155 3.2 5.2 13 100 1.5 1.0 0.65 Ω Conditions Normal mode Sleep mode V ±1 ±1 VREF Unit mA µA mA V KHz 0.75 × VDD VIH toff tSE tcon tcoff 0.4 0.24 1.2 2.1 0.25 × VDD VSENSE Switching Time 0.25 0.18 0.95 0.95 VIL SENSE Detection Voltage PWM OFF-Time Sleep-Enable Recovery Time 100 250 VREFS IREF PWM Minimum ON-Time Rating Typ. Max. 15 100 5 VF REF Input Current Sense Resistor2) Min. 0.7 VREF + 0.03 0.211 0.160 V V µA V Ω µs µs µs µs µs µs 0.75 2.0 A device 3.0 A device Sleep1 mode1) 2.0 A device 3.0 A device B_SEL = Low B_SEL = High Phase IN Output ON Phase IN Output OFF V Motor coils shorted IOCP 3.5 4.6 A A 2.0 A device 3.0 A device topp 2 µs From PWM-OFF Ttsd 140 °C VFlagL VFlagH 1.25 VDD − 1.25 V Measured at back of device case (after heat has saturated) IFlagL = 1.25 mA V IFlagH = −1.25 mA IFlagL 1.25 mA −1.25 IFlagH mA NOTE: Unless specifically noted, negative current is defined as output current flow from a specified pin. 1) In a state of: IBBS, and output OFF. 2) Includes approximately 5 mΩ circuit resistance in addition to the resistance of the built-in resistor itself. 3) Protection circuit operates when VSENSE ≥ VOCP. FLAG Output Current Sanken Electric Co., Ltd. 4 / 26 SLA7080MS Series Datasheet Rev.1.7 Figure 4-1. Setting Range of Reference Voltage, VREF VDD Sleep1 Set Range 2.0 V Prohibition Zone VOCP = 0.7 V 0.45 V 0.4 V 0.04 V 2.0 A Device 3.0 A Device Motor Current Set Range NOTE: Extra attentions should be paid to the changeover between the motor current specification range and the Sleep1 set range. VOCP falls on the “prohibition zone” threshold. If the changeover takes too long, OCP operation will start when VSENSE > VOCP. 5. Power Derating Chart Figure 5-1. Power Derating Chart Sanken Electric Co., Ltd. 5 / 26 SLA7080MS Series Datasheet Rev.1.7 6. Package Outline Drawing JAPAN a b Leadform 2151 12345 ･ ･ ･ ･ ･ ･ 23 NOTES: ● Dimensions in millimeters ● Pin material: Cu ● Pin plating: Solder plating (Pb-free) ● Branding codes: Part number: SLA708xMS • The lowercase letter x represents a number of either of 2 or 3, according to rated current. See also Table 3-1. Lot number: YMDD • Y is the last digit of the year of manufacture • M is the month of the year (1 to 9, O, N, or D) • DD is the day of the month (01 to 31) Sanken Electric Co., Ltd. 6 / 26 SLA7080MS Series Datasheet Rev.1.7 7. Functional Block Diagram and Pin Assignment 6 10 14 OUTB OUTB 20 21 22 23 11 MIC OUTB 7 OUTB 8 VBB 9 VDD INA 18 INA 13 INB 4 INB OUTA 3 B_SEL OUTA 2 FLAG OUTA 1 REF/SLEEP1 OUTA Figure 7-1. SLA7080 Series Functional Block Diagram Reg. PreDriver PreDriver Logic Block Protection Protection TSD + SENSEA 5 - Rs + Synchro Control Comp PWM Control Comp PWM Control OSC OSC Pin No. Symbol 1, 2 OUTA 3, 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20, 21 22, 23 17 12 15 16 SYNC GND GND1 GND2 Rs Phase A output ___ OUTA SENSEA B_SEL INA Phase A output Phase A current sensing Blanking time switching input _______ Switching input for Phase A ______ Switching input for Phase B INA INB INB VBB GND REF/SLEEP VDD GND1 GND2 SYNC FLAG SENSEB OUTB OUTB SENSEB Function ___________ ___________ 19 - Main power supply voltage (for motor) Device ground Input for control current / Sleep setting Logic power supply Ground 1 Ground 2 PWM control switch input Output from protection circuit monitor Phase B current sensing ___ Phase B output Phase B output Sanken Electric Co., Ltd. 7 / 26 SLA7080MS Series Datasheet Rev.1.7 8. Application Example Figure 8-1. Application Example VBB = 10 to 44 V ＋ CA VDD = 3.0 to 5.5 V SLEEP Q1 R1 OUTA VDD INA INA INB INB SYNC B_SEL ＋ CB MicroController OUTA VBB OUTB OUTB SLA7080MS Series FLAG REF/SLEEP SENSEA GND1 GND GND2 SENSEB R8 R7 R6 R5 R4 R3 R2 Single-Point Ground Logic Ground Constants, for reference use only: R1 = 10 kΩ R2 = 1 kΩ (VR) R3 to R8 = 1 to 10 kΩ (Not required if input state does not reach indefinite.) Power Ground CA = 100 µF / 50 V CB = 10 µF / 10 V C1 = 0.1 µF C2 = 0.1 µF NOTES: ● 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 (INA, INA, INB, INB, B_SEL, and SYNC) must be pulled up or down to VDD or ground. If those unused pins are left open, the device may malfunction or break down. ● Unused logic output pin (FLAG) must be kept open. Sanken Electric Co., Ltd. 8 / 26 SLA7080MS Series Datasheet Rev.1.7 9. Truth Tables (1) Dual Phase Inputs and Outputs The SLA7080MS series allows dual phase operations. The phase-switching logic is shown in Table 9-1. Phase A Table 9-1. Truth Table for Phase-Switching Input Pins _______ INA (Pin 7) Low High Low High INA (Pin 8) Low Low High High OUTA (Pins 1, 2) OFF ON OFF OFF ___________ OUTA (Pins 3,4) OFF OFF ON OFF _______ ___________ Phase B INB OUTB INB OUTB (Pin 9) (Pin 10) (Pins 22, 23) (Pins 20, 21) Low Low OFF OFF High Low ON OFF Low High OFF ON High High OFF OFF NOTE: OUTx indicates power MOSFET drain state (does not indicate PWM operation). (2) Logic Input Pins Table 9-2 explains the logic for input pins other than the phase-switching input logic described above. Table 9-2. Truth Table for Logic Input Pins Pin Name Low Level High Level SYNC Non-sync PWM control Synchronous PWM control B_SEL Blanking time: 3.2 µs Blanking time: 5.2 µs (3) Logic Output Pin (FLAG) Table 9-3 shows the logic for monitor output. Table 9-3. Truth Table for Monitor Output Pin Pin Name Low Level High Level FLAG Normal operation Protection circuit operation NOTE: The output turns off at the point where the protection circuit starts operating. To release the protection state, cycle the logic supply voltage, VDD. Logic Input Pins ________ ________ The low pass filter (LPF) incorporated with the logic input pins (INA, INA, INB, INB, SYNC, and B_SEL) improves noise rejection. The logic inputs are CMOS input compatible; therefore, they are in a high impedance state. Note that the IC should be used at a fixed input level, either low or high. If there is a possibility that signals from the microcontroller are in high impedance, add a pull-up/-down resistor. Since outputs from the logic input pins, which function as output ON/OFF controllers, may result in abnormal oscillation, leading to MOSFET breakdown as the worst-case scenario. Sanken Electric Co., Ltd. 9 / 26 SLA7080MS Series Datasheet Rev.1.7 10. Individual Circuit Descriptions (1) Monolithic IC (MIC) • Logic Block A circuit block that operates with the logic power supply, VDD, and transmits signals to each circuit in accordance with logic input signals. • PWM Control Circuits that allow self-excitation PWM current controlling with a fixed OFF-time are used in this series. Each built-in oscillator (OSC) determines an OFF-time and a blanking time for proper PWM operation. For more detailed functional descriptions, see Section 11. • Synchronous Control A synchronous chopping circuit that prevents occasional motor noise during a hold state which normally results from the asynchronous PWM operation of both motor phases. When the SYNC input pin is set to logic high, the circuit sends a timing signal that simultaneously turns off the chopping of phases A and B. This function adopts the same operation mechanism applied to the SLA7070M series. The use of the synchronous control during normal stepping is not recommended, because it produces less motor torque or may cause motor vibration due to staircase current. • Regulator Circuit An integrated regulator circuit is used for powering the output MOSFET gate drive circuit (pre-driver) and other internal linear circuits. • Protection Circuit Built-in protection circuits against motor coil opens or shorts are provided. This protection is activated by sensing the voltage across internal sense resistors, RS. Therefore, an overcurrent condition cannot be detected which results from the OUTx pins or SENSEx pins, or both, shorting to GND. The 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 a high speed. The operation of the protection circuit disables all outputs. To come out of the Protection mode, cycle the logic supply, VDD. For more details, see the next section. • TSD Circuit A TSD circuit that protects a driver by shifting an output to the Disable mode is incorporated. When the temperature of the product control IC (MIC) rises and becomes higher than its threshold, the circuit starts operating. To reset the function, perform the same steps as described in the Protection Circuit description. Sanken Electric Co., Ltd. 10 / 26 SLA7080MS Series Datasheet Rev.1.7 (2) Output MOSFET Chip The type of MOSFET chips to be mounted varies according to which of the two different output current ratings has been selected. For specifications, see Table 4-3. Rated Current (A) Resistance (Ω Typ.) 2.0 0.25 3.0 0.18 NOTE: Each resistance shown above includes approximately 5 mΩ circuit resistance in addition to the resistance of the built-in resistor itself. (3) Sense Resistor Sense resistors are incorporated in this series to detect motor current. The resistance of these varies according to which of the two different output current ratings has been selected. For specifications, see Table 4-3. Rated Current (A) Resistance (Ω Typ.) 2.0 0.205 3.0 0.155 NOTE: Each resistance shown above includes approximately 5 mΩ circuit resistance in addition to the resistance of the built-in resistor itself. Sanken Electric Co., Ltd. 11 / 26 SLA7080MS Series Datasheet Rev.1.7 11. Functional Descriptions (1) PWM Current Control [1] Blanking Time An actual operating waveform on the SENSEx pin when driving a motor are shown in Figure 11-1. Figure 11-1. Operating Waveforms on SENSEx Pin during PWM Chopping (Circled area of the left panel is shown in expanded scale in the right panel) Immediately after a PWM turns off, ringing (or spike) noise on the SENSEx pin is observed for a period of a few microseconds. Ringing noise can be generated by various causes, such as capacitance between motor coils or inappropriate motor wiring. Each pair of outputs is controlled by a fixed OFF-time PWM current-control circuit that limits the load current to a target value, ITRIP. Initially, an output is enabled and then currents flow through the motor winding and the current sense resistors. When the voltage across the current sense resistors equals the DAC output voltage, VTRIP, the current sense comparator resets a PWM latch. This turns off the driver for the fixed OFF-time, during which the load inductance causes the current to recirculate for the OFF-time period. Therefore, if the ringing noise on the current sense resistor(s) equals and surpasses VTRIP, the PWM turns off (i.e., a hunting phenomenon). To prevent this phenomenon, a blanking time is set to override signals from the current sense comparator for a certain period immediately after the PWM turns on (Figure 11-2). Figure 11-2. SENSEx Pin Waveform Pattern during PMW Control PWM Pulse Width ON OFF (Fixed) ITRIP A 0 A Blanking Time Sanken Electric Co., Ltd. 12 / 26 SLA7080MS Series Datasheet Rev.1.7 [2] Blanking Time and Hunting Phenomenon Although current control can be improved by shortening a blanking time, the degree of margin to a ringing noise decreases simultaneously. For this reason, when a motor is driven by the device, a hunting phenomenon may occur. Figure 11-3 shows an example of the waveform pattern when the phenomenon occurs. In order to overcome this problem, the SLA7080MS series is designed to have the B_SEL pin, allowing the dynamic selection of blanking time duration. In the event that the seeking behavior occurs with a shorter blanking time of 3.2 μs, it may be eased by selecting a longer blanking time of 5.2 μs. Figure 11-3. Example of SENSEx Pin Waveform during Hunting Phenomenon [3] Blanking Time Difference Table 11-1 shows characteristic differences between two blanking times, shorter and longer blanking periods. This comparison is based on the case where drive conditions, such as a motor, motor power supply voltage, REF input voltage, and circuit constant were kept the same while only the indicated parameters were changed. Table 11-1. Characteristic Comparison of Difference in Blanking Time Parameter Internal blanking time Minimum PWM ON-time Better Performance Short Small Ringing noise suppression Minimum coil current Long Large Small The following are the brief descriptions of the parameters in Table 11-1: • Minimum PWM ON-time, tON(min) This series has a blanking time that is effectively selected and fixed by the PWM control. Therefore, even if an application attempts to shorten its ON-time for limiting currents, it would not go below the fixed blanking time. Minimum PWM ON-time refers to the time when an output is on during this blanking time period, that is, when an output MOSFET is actually turned on. In other words, a blanking time determines a minimum ON-time (“Small” in Table 11-1). • Minimum Coil Current This refers to the coil current when the PWM control is performed during a minimum PWM ON-time. In other words, the device with a shorter blanking time can reduce more coil current. Sanken Electric Co., Ltd. 13 / 26 SLA7080MS Series Datasheet Rev.1.7 [4] PWM OFF-time PWM OFF-time for the SLA7080MS series is controlled at a fixed time generated by the corresponding internal oscillator. In addition, the SLA7080MS series provides a function that decreases power losses occurring when the PWM turns off. This function dissipates the back EMF stored in the motor coil at MOSFET turn-on, as well as at PWM turn-on (synchronous rectification operation). Figure 11-4 explains differences between two back EMF generation mechanisms. Whereas the older version of our product series only performs ON/OFF operations using a MOSFET on the PWM-ON side, the SLA7080MS series can perform ON/OFF operations using a MOSFET on the PWM-OFF side. To prevent simultaneous switching of the output MOSFETs at the synchronous rectification operation, the IC has a dead time of approximately 0.5 μs. During the dead time, the back EMF flows through the body diodes of the MOSFETs. Figure 11-4. Difference in Back EMF Generation Vcc Normal Rectification Operation Ion Vcc Synchronous Rectification Operation Ion Ioｆｆ Ioｆｆ SPM Vg SPM Vg Vrs PWM ON Rs PWM OFF Vg Vg Vrs PWM ON PWM ON Rs PWM OFF Back EMF at Dead Time PWM ON Dead Time FET Gate Signal Vg 0 FET Gate Signal Vg VREF Sense Voltage 0 VRS FET Gate Signal Vg 0 FET Gate Signal Vg VREF Sense Voltage 0 VRS Back EMF flows through the body diode of MOFSET during dead time . Sanken Electric Co., Ltd. 14 / 26 SLA7080MS Series Datasheet Rev.1.7 (2) Protection Functions The SLA7080MS series includes a motor coil short protection circuit, a motor coil open protection circuit, and an overheat protection circuit. Detailed explanations of each protection circuit are provided below. [1] Motor Coil Short Protection (Load Short) Circuit This protection circuit, embedded in the SLA7080MS series, begins to operate when the device detects an increase in the sense resistor voltage level, V RS. The voltage at which the motor coil short-circuit protection circuit starts its operation, VOCP, is set to approximately 0.7 V. Outputs are disabled at the time the protection circuit starts, where VRS exceeds VOCP. Figure 11-5. Motor Coil Short Protection Circuit Operation VM Coil Short Circuit SPM Coil Short Circuit VOCP Normal Operation VREF Vg VRS Rs VRS 0 Output Disable NOTES: ● Overcurrent that flows without passing the sense resister is undetectable. ● To recover the circuit after the protection operates, VDD must be cycled and started up again. [2] Motor Coil Open Protection Circuit (Patent acquired) Driver destruction can occur when one output pin (motor coil) is disconnected in unipolar drive operation. This is because a MOSFET connected after disconnection will be in an avalanche breakdown state, where very high energy is added with back EMF when PWM is off. With the 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 (i.e., the condition in which the breakdown occurred). Although MOSFETs with a certain amount of an avalanche energy tolerance rating are used in the SLA7080MS series, the avalanche energy tolerance falls as a temperature increases. Because high energy is added repeatedly whenever PWM operation 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 is added in the SLA7080MS series. As explained above, when the motor coil is disconnected, accumulated voltage in the MOSFET causes a reverse current to flow during a PWM OFF-time. For this reason, VRS that is negative during a PWM OFF-time in a normal operation becomes positive when the motor coil is disconnected. Thus, the disconnected motor is detectable by sensing that VRS in the PWM OFF-time is positive. Sanken Electric Co., Ltd. 15 / 26 SLA7080MS Series Datasheet Rev.1.7 In order to avoid detection malfunctions, the SLA7080MS series actuates a dedicated protection function, the motor coil open protection circuit, when the motor disconnection state is detected three times continuously (see Figure 11-6). Figure 11-6. Coil Open Protection Operation PWM Operation at Normal Device Operation PWM Operation at Motor Disconnection VM SPM VM SPM Ion Ioff Disconnecton Vg Vg Vout Vout Vrs Rs Vrs Rs Motor Disconnection FET Gate Signal Vg 0 FET Gate Signal Vg 0 VDSS Vout 2 VM VM Vout 0 0 VREF VRS 0 Breakdown (Avalanche State) VREF VRS 0 Motor Disconnection Detectable NOTE: In addition to requiring three breakdown cycles to confirm the open circuit condition, the SLA7080MS series provides a fixed delay, an overload disconnection undetected time (topp), before the protection is activated. This is to avoid false detections, which can be occurred by surge noise after PWM turn-off, causing an unwanted operation of the function even when the load is not actually disconnected. The figure below describes alternative topp scenarios. If a total period of breakdown time exceeds topp, the device shuts down the output. If this is the case, check the motor and wiring layout to reduce surge noise. Shortening the breakdown time will allow the protection circuit to function properly. (Variation among device variants and applications should be taken into consideration.) When there is no actual breakdown, normal operations will continue. One possible solution is adding a capacitor between the OUTx and GND pins, which could damp the surge noise sufficiently. Sanken Electric Co., Ltd. 16 / 26 SLA7080MS Series Datasheet Rev.1.7 Surge remains under VDSS VDSS VOUT (A) Breakdown confirmed after 3 cycles Breakdown ends w/in topp VDSS VOUT (B) No effect on operations Breakdown continues after topp VDSS VOUT (C) Generates false detections [3] Overheat Protection Circuit When a product temperature rises and exceeds Ttsd, this protection circuit starts operating and sets all outputs to be disabled. NOTE: This product series has multichip composition (one IC for control, four MOSFETs, and two chip resistors). Although main heat sources are the MOSFETs and chip resisters, the location which actually detects temperature is the control IC (MIC). Separated from these main heat sources, the control IC cannot detect a rapid temperature change. Accordingly, perform worst-case thermal evaluations, in which junction temperatures must not exceed a guaranteed value of 150 °C, in your application design phase. Sanken Electric Co., Ltd. 17 / 26 SLA7080MS Series Datasheet Rev.1.7 12. Application Information (1) Motor Current Ratio Setting The motor current, IO, for the SLA7080MS series is determined by the values chosen for the external components, R1 and R2, and the current sense resistors, RS, in the case of the sample application circuit shown in Figure 8-1. The formula to calculate IO is shown below: Io R2 VDD R1 R2 Rs . (1) The double-underlined term represents the reference voltage, VREF. If VREF is set below 0.04 V, the accuracy of IO setting is more likely to be degraded due to the variation between individual devices and/or the impedance of application trace layout. (2) Lower Limit of Control Current The SLA7080MS 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 OFF-time, a coil current flows intermittently, as shown in Figure 12-1. Thus, average current decreases as well as motor torque decreases. The point at which current starts flowing to the coil is considered as the lower limit of the control current, IO(min), where IOUT is the target current level. The lower limit of control current differs by application conditions of the motor or other factors, but it can be calculated from the following formula: I O min Lm , and R R Rm RDS ( on) RS . V M 1 , 1 R t OFF exp t C with t C (2) Where: VM is the motor supply voltage, RDS(on) is the MOS FET on-resistance, Rm is the motor winding resistance, Lm is the motor winding inductance, tOFF is the PWM OFF-time, and RS is the current sense resistor. Even if the control current value is set at less than its lower limit, there is no setting at which the IC fails to operate. However, the control current will worsen against its target current. Figure 12-1. Model Waveform of Control Current Lower Limit ITRIP (Large) A ITRIP (Small) 0 A The circled area indicates interval when the coil current generated is 0 A. Sanken Electric Co., Ltd. 18 / 26 SLA7080MS Series Datasheet Rev.1.7 (3) Avalanche Energy In the unipolar topology of the SLA7080MS series, a surge voltage (ringing noise) that exceeds the MOSFET capacity to withstand might be applied to the IC. To prevent damage, the SLA7080MS series is designed with built-in MOSFETs having sufficient avalanche resistance to withstand this surge voltage. VM Therefore, even if surge voltages occur, users will be able to use the IC without any problems. SPM However, in case the motor harness used is too long or the ID 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 VDS(AV) the avalanche energy applied to the IC under actual application conditions. The following procedure can be used to check the Rs avalanche energy in an application. Figure 12-2 and Figure 12-3 show test points and waveform characteristics resultant, Figure 12-2. Test Points respectively. From the waveform test result shown in Figure 12-3: VDS(AV) = 140 V, ID = 1 A, and t = 0.5 µs. VDS(AV) The avalanche energy, EAV, then can be calculated using the following formula: EAV ≈ VDS(AV) × 1/2 × ID × t = 140 (V) × 1/2 × 1 (A) × 0.5 × 10−6 (μs) = 0.035 (mJ). (3) ID t Figure 12-3. Waveform at Avalanche Breakdown By comparing the calculated EAV values with the graph shown in Figure 12-4, the application can be evaluated if it is safe for the IC by being within the avalanche energy-tolerated dose range of the MOFSETs. Figure 12-4. Iterated Avalanche Energy Tolerated Level, EAV Sanken Electric Co., Ltd. 19 / 26 SLA7080MS Series Datasheet Rev.1.7 (4) ON/OFF Sequence of Power Supply (VBB and VDD) There is no restriction for the ON/OFF sequences of the main power supply, VBB, and the logic supply, VDD. (5) Motor Supply Voltage (VM) and Main Power Supply Voltage (VBB) Because the SLA7080MS series has a structure that separates the control IC (MIC) and the power MOSFETs as shown in Figure 7-1, the motor supply and main power supply are electrically separated. Therefore, it is possible to drive the IC with using different power supplies and different voltages for the motor supply and the main power supply. (6) Internal Logic Circuits a. Chopping Synchronous Circuit The SLA7080MS series has a chopping synchronous function to protect from abnormal noises that may occasionally occur during the motor Hold mode. 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 that may result in reduced motor torque and/or increased vibration. Figure 12-5. Timing Delay between b. Output Disable Circuit (Sleep) Disable Mode Cancellation and The SLA7080MS series can be set into the the Next Phase Input Sleep mode, in which the motor is in a free state. To enable this function, set the REF pin at more than 2 V. In the Sleep mode, the IC stops the main power supply and reduces circuit current. When awaking to the normal operation mode (motor rotation) from the Sleep mode, set an appropriate delay time, i.e., a time period from cancellation of the Sleep mode to the next motor phase input command. In doing so, consider not only a rise time for the IC, but also a rise time for the motor excitation current (Figure 12-5). c. REF/SLEEP1 Pin The REF pin provides access to the following functions: [1] Reference voltage setting for output current level setting: Low level (VREF ≤ 0.3 to 0.45 V, depends on rated currents) [2] Output Enable-Disable control input: High level (VREF ≥ 2.0 V) These functions are further described in Section 9, and in the discussion of output disabling, above. Moreover, the threshold voltage to switch the output enable-disable signals is set to approximately 1.75 V. To control the REF voltage, pay attention to the following points: Range A – Control current value varies in accordance with VREF, not only within the range specified in [1], but also within the range from [1] to the threshold voltage (typically 1.75 V). Therefore, power dissipation in the IC and the sense resistors must be given extra consideration. In addition, note that OCP operation may start depending on the reference voltage splitting ratio. Range B – In this range, the voltage that switches output enable and disable exists. At enable, the same cautions apply as in Range A. For some cases, there are possibilities that an output status will become unstable as a result of iterations between enable and disable states. Sanken Electric Co., Ltd. 20 / 26 SLA7080MS Series Datasheet Rev.1.7 d. Logic Pins ________ ________ • Logic Input Pins (INA, INA, INB, INB, SYNC, and B_SEL) ________ ________ When a logic input pin (INA, INA, INB, INB, SYNC, or B_SEL) is not used, the pin must be tied to VDD or GND. Do not leave any of these pins floating, because there is possibility of undefined effects on IC performance if they are left open. • Monitor Output Pin (FLAG) The FLAG pin is designed as a monitor output. Moreover, the IC consists of an inverter output configuration, as shown in Figure 12-6. Therefore, let the pin open when it is not used. Figure 12-6. FLAG Pin General Internal Circuit Layout VDD Static Electricity Protection Circuit Sanken Electric Co., Ltd. FLAG 21 / 26 SLA7080MS Series Datasheet Rev.1.7 13. Thermal Design Information It is not practical to calculate the power dissipation of the SLA7080MS 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 approximate calculations at worst conditions. The following is a simplified formula for the calculation of power dissipation using extracted minimum necessary parameters: P I 2 (R DS(on)＋Rs) 2 , where: P is the power dissipation in the IC, I is the operation current (≈ IO), RDS(on) is the on-resistance of the output MOSFET, and Rs is the current sense resistance. Based on the power dissipation in the IC calculated using the above formula, the expected increase in operating junction temperature, ΔTJ, of the IC can be estimated using Figure 13-1. This result should be added to the worst-case ambient temperature when operating, TA(max). Based on the calculation, there is no problem unless TA(max) + ΔTJ > 150 °C. However, final confirmation should be made by measuring the IC temperature during operation and then verifying power dissipation and junction temperature in the corresponding graph in Figure 13-1. Figure 13-1. Temperature Increase When the IC is used with a heatsink mounted, product package thermal resistance, θJ-A, is a variable used in calculating ΔTJ-A. The value of θJ-A is calculated from the following formula: θJ-A ≈ θJ-C + θFIN = (θJ-A – θC-A) + θFIN , where θFIN is the thermal resistance of the heatsink. Then, ΔTJ-A can be calculated with using the value of θJ-A. Sanken Electric Co., Ltd. 22 / 26 SLA7080MS Series Datasheet Rev.1.7 The following procedure should be used to measure product temperature and to estimate junction temperature in actual operation. First, measure a temperature rise in the center of backside of mold resin used for the device (ΔTC-A). Second, estimate power dissipation (P) and junction temperature (TJ) from the temperature rise with reference to Figure 13-1, the Temperature Increase graph. At this point, the device temperature rise (ΔTC-A) and the junction temperature rise (TJ) become almost equivalent in the following formula: ΔTJ ≈ ΔTC-A + P × θJ-C . CAUTION The SLA7080MS series is designed as a multichip, consisting of four separate power elements (MOSFETs), one control IC (MIC), and two sense resistors. Moreover, because the control IC cannot accurately detect the temperature of the built-in power elements, which are the primary sources of heat, the SLA7080MS series does not provide a protection function against overheating. For thermal protection, users must conduct sufficient thermal evaluations to ensure that the junction temperature of the IC does not exceed a guaranteed level of 150 °C. This thermal design information is provided for preliminary design estimations only. Before operating the IC in an application, users must experimentally determine its actual thermal performance (the case temperature of Pin 12). The maximum recommended case temperatures (Pin 12) for the IC are: With no external heatsink connection: 90 °C With external heatsink connection: 80 °C Sanken Electric Co., Ltd. 23 / 26 SLA7080MS Series Datasheet Rev.1.7 14. Characteristics Data (1) Output MOSFET On-Voltage, VDS(on) (2) Output MOSFET Body Diodes Forward Voltage, VF Sanken Electric Co., Ltd. 24 / 26 SLA7080MS Series Datasheet Rev.1.7 Important Notes All data, illustrations, graphs, tables and any other information included in this document as to Sanken’s products listed herein (the “Sanken Products”) are current as of the date this document is issued. All contents in this document are subject to any change without notice due to improvement of the Sanken Products, etc. Please make sure to confirm with a Sanken sales representative that the contents set forth in this document reflect the latest revisions before use. The Sanken Products are intended for use as components of general purpose electronic equipment or apparatus (such as home appliances, office equipment, telecommunication equipment, measuring equipment, etc.). Prior to use of the Sanken Products, please put your signature, or affix your name and seal, on the specification documents of the Sanken Products and return them to Sanken. When considering use of the Sanken Products for any applications that require higher reliability (such as transportation equipment and its control systems, traffic signal control systems or equipment, disaster/crime alarm systems, various safety devices, etc.), you must contact a Sanken sales representative to discuss the suitability of such use and put your signature, or affix your name and seal, on the specification documents of the Sanken Products and return them to Sanken, prior to the use of the Sanken Products. The Sanken Products are not intended for use in any applications that require extremely high reliability such as: aerospace equipment; nuclear power control systems; and medical equipment or systems, whose failure or malfunction may result in death or serious injury to people, i.e., medical devices in Class III or a higher class as defined by relevant laws of Japan (collectively, the “Specific Applications”). Sanken assumes no liability or responsibility whatsoever for any and all damages and losses that may be suffered by you, users or any third party, resulting from the use of the Sanken Products in the Specific Applications or in manner not in compliance with the instructions set forth herein. In the event of using the Sanken Products by either (i) combining other products or materials therewith or (ii) physically, chemically or otherwise processing or treating the same, you must duly consider all possible risks that may result from all such uses in advance and proceed therewith at your own responsibility. Although Sanken is making efforts to enhance the quality and reliability of its products, it is impossible to completely avoid the occurrence of any failure or defect in semiconductor products at a certain rate. You must take, at your own responsibility, preventative measures including using a sufficient safety design and confirming safety of any equipment or systems in/for which the Sanken Products are used, upon due consideration of a failure occurrence rate or derating, etc., in order not to cause any human injury or death, fire accident or social harm which may result from any failure or malfunction of the Sanken Products. Please refer to the relevant specification documents and Sanken’s official website in relation to derating. No anti-radioactive ray design has been adopted for the Sanken Products. No contents in this document can be transcribed or copied without Sanken’s prior written consent. The circuit constant, operation examples, circuit examples, pattern layout examples, design examples, recommended examples, all information and evaluation results based thereon, etc., described in this document are presented for the sole purpose of reference of use of the Sanken Products and Sanken assumes no responsibility whatsoever for any and all damages and losses that may be suffered by you, users or any third party, or any possible infringement of any and all property rights including intellectual property rights and any other rights of you, users or any third party, resulting from the foregoing. All technical information described in this document (the “Technical Information”) is presented for the sole purpose of reference of use of the Sanken Products and no license, express, implied or otherwise, is granted hereby under any intellectual property rights or any other rights of Sanken. Unless otherwise agreed in writing between Sanken and you, Sanken makes no warranty of any kind, whether express or implied, including, without limitation, any warranty (i) as to the quality or performance of the Sanken Products (such as implied warranty of merchantability, or implied warranty of fitness for a particular purpose or special environment), (ii) that any Sanken Product is delivered free of claims of third parties by way of infringement or the like, (iii) that may arise from course of performance, course of dealing or usage of trade, and (iv) as to any information contained in this document (including its accuracy, usefulness, or reliability). In the event of using the Sanken Products, you must use the same after carefully examining all applicable environmental laws and regulations that regulate the inclusion or use of any particular controlled substances, including, but not limited to, the EU RoHS Directive, so as to be in strict compliance with such applicable laws and regulations. You must not use the Sanken Products or the Technical Information for the purpose of any military applications or use, including but not limited to the development of weapons of mass destruction. In the event of exporting the Sanken Products or the Technical Information, or providing them for non-residents, you must comply with all applicable export control laws and regulations in each country including the U.S. Export Administration Regulations (EAR) and the Foreign Exchange and Foreign Trade Act of Japan, and follow the procedures required by such applicable laws and regulations. Sanken Electric Co., Ltd. 25 / 26 SLA7080MS Series Datasheet Rev.1.7 Sanken assumes no responsibility for any troubles, which may occur during the transportation of the Sanken Products including the falling thereof, out of Sanken’s distribution network. Although Sanken has prepared this document with its due care to pursue the accuracy thereof, Sanken does not warrant that it is error free and Sanken assumes no liability whatsoever for any and all damages and losses which may be suffered by you resulting from any possible errors or omissions in connection with the contents included herein. Please refer to the relevant specification documents in relation to particular precautions when using the Sanken Products, and refer to our official website in relation to general instructions and directions for using the Sanken Products. DSGN-CEZ-16001 Sanken Electric Co., Ltd. 26 / 26