DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 www.ti.com STEPPER MOTOR CONTROLLER IC Check for Samples: DRV8825 FEATURES APPLICATIONS • • • • • • • • • • 1 2 • • • • PWM Microstepping Motor Driver – Built-In Microstepping Indexer – Five-Bit Winding Current Control Allows Up to 32 Current Levels – Low MOSFET On-Resistance 2.5-A Maximum Drive Current at 24 V, 25°C Built-In 3.3-V Reference Output 8.2-V to 45-V Operating Supply Voltage Range Thermally Enhanced Surface Mount Package Automatic Teller Machines Money Handling Machines Video Security Cameras Printers Scanners Office Automation Machines Gaming Machines Factory Automation Robotics DESCRIPTION The DRV8825 provides an integrated motor driver solution for printers, scanners, and other automated equipment applications. The device has two H-bridge drivers, and can drive a bipolar stepper motor or two DC motors. The output driver block for each consists of N-channel power MOSFET’s configured as full H-bridges to drive the motor windings. The DRV8825 can supply up to 2.5-A peak or 1.75-A RMS output current (with proper heatsinking at 24 V and 25°C). A simple step/direction interface allows easy interfacing to controller circuits. Pins allow configuration of the motor in full-step up to 1/32-step modes. Decay mode is programmable. Internal shutdown functions are provided for overcurrent protection, short circuit protection, undervoltage lockout and overtemperature. The DRV8825 is available in a 28-pin HTSSOP package with PowerPAD™ (Eco-friendly: RoHS & no Sb/Br). ORDERING INFORMATION (1) TA –40°C to 85°C (1) (2) PACKAGE (2) PowerPAD™ (HTSSOP) - PWP Reel of 2000 ORDERABLE PART NUMBER TOP-SIDE MARKING DRV8825PWPR 8825 For the most current packaging and ordering information, see the Package Option Addendum at the end of this document, or see the TI web site at www.ti.com. Package drawings, thermal data, and symbolization are available at www.ti.com/packaging. 1 2 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. PowerPAD is a trademark of Texas Instruments. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2010–2011, Texas Instruments Incorporated DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 www.ti.com DEVICE INFORMATION Functional Block Diagram VM VM Internal Reference & Regs Int. VCC CP1 LS Gate Drive 0.01 mF Charge Pump V3P3OUT 3.3 V CP2 VM 3.3 V VCP Thermal Shut down 0.1 mF HS Gate Drive AVREF VM VMA BVREF AOUT1 + Step Motor Motor Driver A nENBL AOUT2 STEP - DIR + ISENA - DECAY MODE0 MODE1 MODE2 Indexer / Control Logic VM VMB nRESET BOUT1 nSLEEP Motor Driver B nHOME BOUT2 nFAULT ISENB GND 2 GND Copyright © 2010–2011, Texas Instruments Incorporated DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 www.ti.com Table 1. TERMINAL FUNCTIONS NAME PIN I/O (1) EXTERNAL COMPONENTS OR CONNECTIONS DESCRIPTION POWER AND GROUND GND 14, 28 - Device ground VMA 4 - Bridge A power supply VMB 11 - Bridge B power supply V3P3OUT 15 O 3.3-V regulator output CP1 1 IO Charge pump flying capacitor CP2 2 IO Charge pump flying capacitor VCP 3 IO High-side gate drive voltage Connect a 0.1-μF 16-V ceramic capacitor to VM. nENBL 21 I Enable input Logic high to disable device outputs and indexer operation, logic low to enable. Internal pulldown. nSLEEP 17 I Sleep mode input Logic high to enable device, logic low to enter low-power sleep mode. Internal pulldown. STEP 22 I Step input Rising edge causes the indexer to move one step DIR 20 I Direction input Level sets the direction of stepping MODE0 24 I Microstep mode 0 MODE1 25 I Microstep mode 1 MODE2 26 I Microstep mode 2 DECAY 19 I Decay mode Low = slow decay, open = mixed decay, high = fast decay. Internal pulldown and pullup. nRESET 16 I Reset input Active-low reset input initializes the indexer logic and disables the H-bridge outputs. Internal pulldown. AVREF 12 I Bridge A current set reference input BVREF 13 I Bridge B current set reference input nHOME 27 OD Home position Logic low when at home state of step table nFAULT 18 OD Fault Logic low when in fault condition (overtemp, overcurrent) ISENA 6 IO Bridge A ground / Isense Connect to current sense resistor for bridge A. ISENB 9 IO Bridge B ground / Isense Connect to current sense resistor for bridge B. AOUT1 5 O Bridge A output 1 AOUT2 7 O Bridge A output 2 Connect to bipolar stepper motor winding A. Positive current is AOUT1 → AOUT2 BOUT1 10 O Bridge B output 1 BOUT2 8 O Bridge B output 2 Connect to motor supply (8.2 - 45 V). Both pins must be connected to same supply. Bypass to GND with a 0.47-μF 6.3-V ceramic capacitor. Can be used to supply VREF. Connect a 0.01-μF 50-V capacitor between CP1 and CP2. CONTROL MODE0 - MODE2 set the step mode - full, 1/2, 1/4, 1/8/ 1/16, or 1/32 step Reference voltage for winding current set. Normally AVREF and BVREF are connected to the same voltage. Can be connected to V3P3OUT. STATUS OUTPUT (1) Connect to bipolar stepper motor winding B. Positive current is BOUT1 → BOUT2 Directions: I = input, O = output, OZ = tri-state output, OD = open-drain output, IO = input/output Copyright © 2010–2011, Texas Instruments Incorporated 3 DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 4 www.ti.com Copyright © 2010–2011, Texas Instruments Incorporated DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 www.ti.com ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) VMx VREF (1) (2) VALUE UNIT Power supply voltage range –0.3 to 47 V Digital pin voltage range –0.5 to 7 V Input voltage –0.3 to 4 V –0.3 to 0.8 V Peak motor drive output current, t < 1 μS Internally limited A Continuous motor drive output current (3) 2.5 A ISENSEx pin voltage ESD rating HBD (human body model) 2000 CDM (charged device model) 500 Continuous total power dissipation See Dissipation Ratings table –40 to 150 °C Operating ambient temperature range –40 to 85 °C Storage temperature range –60 to 150 °C TJ Operating virtual junction temperature range TA Tstg (1) (2) (3) V Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied. Exposure to absolute maximum rated conditions for extended periods may affect device reliability. All voltage values are with respect to network ground terminal. Power dissipation and thermal limits must be observed. THERMAL INFORMATION DRV8825 THERMAL METRIC (1) PWP UNITS 28 PINS θJA Junction-to-ambient thermal resistance (2) 31.6 θJCtop Junction-to-case (top) thermal resistance (3) 15.9 (4) θJB Junction-to-board thermal resistance ψJT Junction-to-top characterization parameter (5) 0.2 ψJB Junction-to-board characterization parameter (6) 5.5 θJCbot Junction-to-case (bottom) thermal resistance (7) 1.4 (1) (2) (3) (4) (5) (6) (7) 5.6 °C/W For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953. The junction-to-ambient thermal resistance under natural convection is obtained in a simulation on a JEDEC-standard, high-K board, as specified in JESD51-7, in an environment described in JESD51-2a. The junction-to-case (top) thermal resistance is obtained by simulating a cold plate test on the package top. No specific JEDEC-standard test exists, but a close description can be found in the ANSI SEMI standard G30-88. The junction-to-board thermal resistance is obtained by simulating in an environment with a ring cold plate fixture to control the PCB temperature, as described in JESD51-8. The junction-to-top characterization parameter, ψJT, estimates the junction temperature of a device in a real system and is extracted from the simulation data for obtaining θJA, using a procedure described in JESD51-2a (sections 6 and 7). The junction-to-board characterization parameter, ψJB, estimates the junction temperature of a device in a real system and is extracted from the simulation data for obtaining θJA , using a procedure described in JESD51-2a (sections 6 and 7). The junction-to-case (bottom) thermal resistance is obtained by simulating a cold plate test on the exposed (power) pad. No specific JEDEC standard test exists, but a close description can be found in the ANSI SEMI standard G30-88. RECOMMENDED OPERATING CONDITIONS over operating free-air temperature range (unless otherwise noted) MIN (1) NOM MAX UNIT VM Motor power supply voltage range 8.2 45 VREF VREF input voltage (2) 1 3.5 IV3P3 V3P3OUT load current 0 1 mA fPWM Externally applied PWM frequency 0 100 kHz (1) (2) V V All VM pins must be connected to the same supply voltage. Operational at VREF between 0 V and 1 V, but accuracy is degraded. Copyright © 2010–2011, Texas Instruments Incorporated 5 DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 www.ti.com ELECTRICAL CHARACTERISTICS over operating free-air temperature range (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT POWER SUPPLIES IVM VM operating supply current VM = 24 V, fPWM < 50 kHz 5 8 mA IVMQ VM sleep mode supply current VM = 24 V 10 20 μA VUVLO VM undervoltage lockout voltage VM rising 7.8 8.2 V 3.3 3.4 V V3P3OUT REGULATOR V3P3 V3P3OUT voltage IOUT = 0 to 1 mA 3.2 LOGIC-LEVEL INPUTS VIL Input low voltage VIH Input high voltage 2.2 0.6 VHYS Input hysteresis 0.3 IIL Input low current VIN = 0 IIH Input high current VIN = 3.3 V RPD Internal pulldown resistance 0.45 –20 0.7 V 5.25 V 0.6 V 20 μA 100 μA 100 kΩ nHOME, nFAULT OUTPUTS (OPEN-DRAIN OUTPUTS) VOL Output low voltage IO = 5 mA IOH Output high leakage current VO = 3.3 V 0.5 V 1 μA 0.8 V ±40 µA DECAY INPUT VIL Input low threshold voltage For slow decay mode VIH Input high threshold voltage For fast decay mode IIN Input current RPU Internal pullup resistance (up to 3.3 V) RPD Internal pulldown resistance 2 V 130 kΩ 80 kΩ H-BRIDGE FETS HS FET on resistance RDS(ON) LS FET on resistance IOFF VM = 24 V, IO = 1 A, TJ = 25°C 0.2 VM = 24 V, IO = 1 A, TJ = 85°C 0.25 VM = 24 V, IO = 1 A, TJ = 25°C 0.2 VM = 24 V, IO = 1 A, TJ = 85°C 0.25 –20 Off-state leakage current 0.32 Ω 0.32 20 μA MOTOR DRIVER fPWM Internal current control PWM frequency 30 kHz tBLANK Current sense blanking time tR Rise time 30 200 ns tF Fall time 30 200 ns 160 180 °C 3 μA 660 685 mV μs 4 PROTECTION CIRCUITS IOCP Overcurrent protection trip level tTSD Thermal shutdown temperature 3 Die temperature 150 A CURRENT CONTROL –3 IREF xVREF input current xVREF = 3.3 V VTRIP xISENSE trip voltage xVREF = 3.3 V, 100% current setting 635 xVREF = 3.3 V, 5% current setting –25 25 xVREF = 3.3 V, 10% - 34% current setting –15 15 xVREF = 3.3 V, 38% - 67% current setting –10 10 xVREF = 3.3 V, 71% - 100% current setting –5 5 ΔITRIP Current trip accuracy (relative to programmed value) AISENSE Current sense amplifier gain 6 Reference only 5 % V/V Copyright © 2010–2011, Texas Instruments Incorporated DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 www.ti.com TIMING REQUIREMENTS MIN MAX UNIT 250 kHz 1 fSTEP Step frequency 2 tWH(STEP) Pulse duration, STEP high 1.9 μs 3 tWL(STEP) Pulse duration, STEP low 1.9 μs 4 tSU(STEP) Setup time, command to STEP rising 650 ns 5 tH(STEP) Hold time, command to STEP rising 650 ns 6 tENBL Enable time, nENBL active to STEP 650 ns 7 tWAKE Wakeup time, nSLEEP inactive to STEP 1.7 ms Figure 1. Timing Diagram Copyright © 2010–2011, Texas Instruments Incorporated 7 DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 www.ti.com FUNCTIONAL DESCRIPTION PWM Motor Drivers The DRV8825 contains two H-bridge motor drivers with current-control PWM circuitry. A block diagram of the motor control circuitry is shown in Figure 2. Figure 2. Motor Control Circuitry Note that there are multiple VM motor power supply pins. All VM pins must be connected together to the motor supply voltage. 8 Copyright © 2010–2011, Texas Instruments Incorporated DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 www.ti.com Current Regulation The current through the motor windings is regulated by a fixed-frequency PWM current regulation, or current chopping. When an H-bridge is enabled, current rises through the winding at a rate dependent on the DC voltage and inductance of the winding. Once the current hits the current chopping threshold, the bridge disables the current until the beginning of the next PWM cycle. In stepping motors, current regulation is used to vary the current in the two windings in a semi-sinusoidal fashion to provide smooth motion. The PWM chopping current is set by a comparator which compares the voltage across a current sense resistor connected to the xISEN pins, multiplied by a factor of 5, with a reference voltage. The reference voltage is input from the xVREF pins. The full-scale (100%) chopping current is calculated in Equation 1. VREFX ICHOP = 5¾ · RISENSE (1) Example: If a 0.25-Ω sense resistor is used and the VREFx pin is 2.5 V, the full-scale (100%) chopping current will be 2.5 V / (5 x 0.25 Ω) = 2 A. The reference voltage is scaled by an internal DAC that allows fractional stepping of a bipolar stepper motor, as described in the microstepping indexer section below. Decay Mode During PWM current chopping, the H-bridge is enabled to drive current through the motor winding until the PWM current chopping threshold is reached. This is shown in Figure 3 as case 1. The current flow direction shown indicates positive current flow. Once the chopping current threshold is reached, the H-bridge can operate in two different states, fast decay or slow decay. In fast decay mode, once the PWM chopping current level has been reached, the H-bridge reverses state to allow winding current to flow in a reverse direction. As the winding current approaches zero, the bridge is disabled to prevent any reverse current flow. Fast decay mode is shown in Figure 3 as case 2. In slow decay mode, winding current is re-circulated by enabling both of the low-side FETs in the bridge. This is shown in Figure 3 as case 3. Figure 3. Decay Mode Copyright © 2010–2011, Texas Instruments Incorporated 9 DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 www.ti.com The DRV8825 supports fast decay, slow decay and a mixed decay mode. Slow, fast, or mixed decay mode is selected by the state of the DECAY pin - logic low selects slow decay, open selects mixed decay operation, and logic high sets fast decay mode. The DECAY pin has both an internal pullup resistor of approximately 130 kΩ and an internal pulldown resistor of approximately 80 kΩ. This sets the mixed decay mode if the pin is left open or undriven. Mixed decay mode begins as fast decay, but at a fixed period of time (75% of the PWM cycle) switches to slow decay mode for the remainder of the fixed PWM period. This occurs only if the current through the winding is decreasing (per the indexer step table); if the current is increasing, then slow decay is used. Blanking Time After the current is enabled in an H-bridge, the voltage on the xISEN pin is ignored for a fixed period of time before enabling the current sense circuitry. This blanking time is fixed at 3.75 μs. Note that the blanking time also sets the minimum on time of the PWM. Microstepping Indexer Built-in indexer logic in the DRV8825 allows a number of different stepping configurations. The MODE0 - MODE2 pins are used to configure the stepping format as shown in Table 2. Table 2. Stepping Format MODE2 MODE1 MODE0 0 0 0 Full step (2-phase excitation) with 71% current STEP MODE 0 0 1 1/2 step (1-2 phase excitation) 0 1 0 1/4 step (W1-2 phase excitation) 0 1 1 8 microsteps / step 1 0 0 16 microsteps / step 1 0 1 32 microsteps / step 1 1 0 32 microsteps / step 1 1 1 32 microsteps / step Table 3 shows the relative current and step directions for different settings of MODEx. At each rising edge of the STEP input, the indexer travels to the next state in the table. The direction is shown with the DIR pin high; if the DIR pin is low the sequence is reversed. Positive current is defined as xOUT1 = positive with respect to xOUT2. Note that if the step mode is changed while stepping, the indexer will advance to the next valid state for the new MODEx setting at the rising edge of STEP. The home state is 45°. This state is entered at power-up or application of nRESET. This is shown in Table 3 by the shaded cells. Table 3. Relative Current and Step Directions 1/32 STEP 1/16 STEP 1 1 1/8 STEP 1/4 STEP 1/2 STEP 1 1 1 2 3 2 4 5 3 2 6 7 4 8 9 5 10 11 10 6 3 2 FULL STEP 70% WINDING CURRENT A WINDING CURRENT B ELECTRICAL ANGLE 100% 0% 0 100% 5% 3 100% 10% 6 99% 15% 8 98% 20% 11 97% 24% 14 96% 29% 17 94% 34% 20 92% 38% 23 90% 43% 25 88% 47% 28 Copyright © 2010–2011, Texas Instruments Incorporated DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 www.ti.com Table 3. Relative Current and Step Directions (continued) 1/32 STEP 1/16 STEP 1/8 STEP 1/4 STEP 1/2 STEP FULL STEP 70% 12 13 7 4 14 15 8 16 17 9 5 3 2 1 18 19 10 20 21 11 6 22 23 12 24 25 13 7 4 26 27 14 28 29 15 8 30 31 16 32 33 17 9 5 3 34 35 18 36 37 19 10 38 39 20 40 41 21 11 6 42 43 22 44 45 23 12 46 47 24 48 49 25 13 7 50 51 26 52 53 27 14 54 55 28 56 57 29 15 8 Copyright © 2010–2011, Texas Instruments Incorporated 4 2 WINDING CURRENT A WINDING CURRENT B ELECTRICAL ANGLE 86% 51% 31 83% 56% 34 80% 60% 37 77% 63% 39 74% 67% 42 71% 71% 45 67% 74% 48 63% 77% 51 60% 80% 53 56% 83% 56 51% 86% 59 47% 88% 62 43% 90% 65 38% 92% 68 34% 94% 70 29% 96% 73 24% 97% 76 20% 98% 79 15% 99% 82 10% 100% 84 5% 100% 87 0% 100% 90 –5% 100% 93 –10% 100% 96 –15% 99% 98 –20% 98% 101 –24% 97% 104 –29% 96% 107 –34% 94% 110 –38% 92% 113 –43% 90% 115 –47% 88% 118 –51% 86% 121 –56% 83% 124 –60% 80% 127 –63% 77% 129 –67% 74% 132 –71% 71% 135 –74% 67% 138 –77% 63% 141 –80% 60% 143 –83% 56% 146 –86% 51% 149 –88% 47% 152 –90% 43% 155 –92% 38% 158 11 DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 www.ti.com Table 3. Relative Current and Step Directions (continued) 1/32 STEP 1/16 STEP 1/8 STEP 1/4 STEP 1/2 STEP FULL STEP 70% 58 59 30 60 61 31 16 62 63 32 64 65 33 17 9 5 66 67 34 68 69 35 18 70 71 36 72 73 37 19 10 74 75 38 76 77 39 20 78 79 40 80 81 41 21 11 6 82 83 42 84 85 43 22 86 87 44 88 89 45 23 12 90 91 46 92 93 47 24 94 95 48 96 97 49 25 98 99 50 100 101 51 102 103 12 52 26 13 7 3 WINDING CURRENT A WINDING CURRENT B ELECTRICAL ANGLE –94% 34% 160 –96% 29% 163 –97% 24% 166 –98% 20% 169 –99% 15% 172 –100% 10% 174 –100% 5% 177 –100% 0% 180 –100% –5% 183 –100% –10% 186 –99% –15% 188 –98% –20% 191 –97% –24% 194 –96% –29% 197 –94% –34% 200 –92% –38% 203 –90% –43% 205 –88% –47% 208 –86% –51% 211 –83% –56% 214 –80% –60% 217 –77% –63% 219 –74% –67% 222 –71% –71% 225 –67% –74% 228 –63% –77% 231 –60% –80% 233 –56% –83% 236 –51% –86% 239 –47% –88% 242 –43% –90% 245 –38% –92% 248 –34% –94% 250 –29% –96% 253 –24% –97% 256 –20% –98% 259 –15% –99% 262 –10% –100% 264 –5% –100% 267 0% –100% 270 5% –100% 273 10% –100% 276 15% –99% 278 20% –98% 281 24% –97% 284 29% –96% 287 Copyright © 2010–2011, Texas Instruments Incorporated DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 www.ti.com Table 3. Relative Current and Step Directions (continued) 1/32 STEP 1/16 STEP 1/8 STEP 1/4 STEP 27 14 1/2 STEP FULL STEP 70% 104 105 53 106 107 54 108 109 55 28 110 111 56 112 113 57 29 15 8 114 115 58 116 117 59 30 118 119 60 120 121 61 31 16 122 123 62 124 125 63 32 126 127 64 128 4 WINDING CURRENT A WINDING CURRENT B ELECTRICAL ANGLE 34% –94% 290 38% –92% 293 43% –90% 295 47% –88% 298 51% –86% 301 56% –83% 304 60% –80% 307 63% –77% 309 67% –74% 312 71% –71% 315 74% –67% 318 77% –63% 321 80% –60% 323 83% –56% 326 86% –51% 329 88% –47% 332 90% –43% 335 92% –38% 338 94% –34% 340 96% –29% 343 97% –24% 346 98% –20% 349 99% –15% 352 100% –10% 354 100% –5% 357 nRESET, nENBLE and nSLEEP Operation The nRESET pin, when driven active low, resets internal logic, and resets the step table to the home position. It also disables the H-bridge drivers. The STEP input is ignored while nRESET is active. The nENBL pin is used to control the output drivers and enable/disable operation of the indexer. When nENBL is low, the output H-bridges are enabled, and rising edges on the STEP pin are recognized. When nENBL is high, the H-bridges are disabled, the outputs are in a high-impedance state, and the STEP input is ignored. Driving nSLEEP low will put the device into a low power sleep state. In this state, the H-bridges are disabled, the gate drive charge pump is stopped, the V3P3OUT regulator is disabled, and all internal clocks are stopped. In this state all inputs are ignored until nSLEEP returns inactive high. When returning from sleep mode, some time (approximately 1 ms) needs to pass before applying a STEP input, to allow the internal circuitry to stabilize. Note that nRESET and nSLEEP have internal pulldown resistors of approximately 100 kΩ. These signals need to be driven to logic high for device operation. Protection Circuits The DRV8825 is fully protected against undervoltage, overcurrent and overtemperature events. Overcurrent Protection (OCP) An analog current limit circuit on each FET limits the current through the FET by removing the gate drive. If this analog current limit persists for longer than the OCP time, all FETs in the H-bridge will be disabled and the nFAULT pin will be driven low. The device will remain disabled until either nRESET pin is applied, or VM is removed and re-applied. Copyright © 2010–2011, Texas Instruments Incorporated 13 DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 www.ti.com Overcurrent conditions on both high and low side devices; i.e., a short to ground, supply, or across the motor winding will all result in an overcurrent shutdown. Note that overcurrent protection does not use the current sense circuitry used for PWM current control, and is independent of the ISENSE resistor value or VREF voltage. Thermal Shutdown (TSD) If the die temperature exceeds safe limits, all FETs in the H-bridge will be disabled and the nFAULT pin will be driven low. Once the die temperature has fallen to a safe level operation will automatically resume. Undervoltage Lockout (UVLO) If at any time the voltage on the VM pins falls below the undervoltage lockout threshold voltage, all circuitry in the device will be disabled and internal logic will be reset. Operation will resume when VM rises above the UVLO threshold. 14 Copyright © 2010–2011, Texas Instruments Incorporated DRV8825 SLVSA73C – APRIL 2010 – REVISED MAY 2011 www.ti.com THERMAL INFORMATION Thermal Protection The DRV8825 has thermal shutdown (TSD) as described above. If the die temperature exceeds approximately 150°C, the device will be disabled until the temperature drops to a safe level. Any tendency of the device to enter TSD is an indication of either excessive power dissipation, insufficient heatsinking, or too high an ambient temperature. Power Dissipation Power dissipation in the DRV8825 is dominated by the power dissipated in the output FET resistance, or RDS(ON). Average power dissipation when running a stepper motor can be roughly estimated by Equation 2. PTOT = 4 · RDS(ON) · (IOUT(RMS)) 2 (2) where PTOT is the total power dissipation, RDS(ON) is the resistance of each FET, and IOUT(RMS) is the RMS output current being applied to each winding. IOUT(RMS) is equal to the approximately 0.7x the full-scale output current setting. The factor of 4 comes from the fact that there are two motor windings, and at any instant two FETs are conducting winding current for each winding (one high-side and one low-side). The maximum amount of power that can be dissipated in the device is dependent on ambient temperature and heatsinking. Note that RDS(ON) increases with temperature, so as the device heats, the power dissipation increases. This must be taken into consideration when sizing the heatsink. Heatsinking The PowerPAD™ package uses an exposed pad to remove heat from the device. For proper operation, this pad must be thermally connected to copper on the PCB to dissipate heat. On a multi-layer PCB with a ground plane, this can be accomplished by adding a number of vias to connect the thermal pad to the ground plane. On PCBs without internal planes, copper area can be added on either side of the PCB to dissipate heat. If the copper area is on the opposite side of the PCB from the device, thermal vias are used to transfer the heat between top and bottom layers. For details about how to design the PCB, refer to TI application report SLMA002, " PowerPAD™ Thermally Enhanced Package" and TI application brief SLMA004, " PowerPAD™ Made Easy", available at www.ti.com. In general, the more copper area that can be provided, the more power can be dissipated. It can be seen that the heatsink effectiveness increases rapidly to about 20 cm2, then levels off somewhat for larger areas. Copyright © 2010–2011, Texas Instruments Incorporated 15 PACKAGE OPTION ADDENDUM www.ti.com 23-May-2011 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Qty Eco Plan (2) Lead/ Ball Finish MSL Peak Temp (3) DRV8825PWP ACTIVE HTSSOP PWP 28 50 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR DRV8825PWPR ACTIVE HTSSOP PWP 28 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR Samples (Requires Login) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. 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Addendum-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 19-May-2011 TAPE AND REEL INFORMATION *All dimensions are nominal Device DRV8825PWPR Package Package Pins Type Drawing SPQ HTSSOP 2000 PWP 28 Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 330.0 16.4 Pack Materials-Page 1 6.9 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 10.2 1.8 12.0 16.0 Q1 PACKAGE MATERIALS INFORMATION www.ti.com 19-May-2011 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) DRV8825PWPR HTSSOP PWP 28 2000 346.0 346.0 33.0 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. 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