SLVSDA5E January   2016  – March 2020 DRV8884

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
      2.      Microstepping Current Waveform
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Indexer Timing Requirements
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Stepper Motor Driver Current Ratings
        1. 7.3.1.1 Peak Current Rating
        2. 7.3.1.2 RMS Current Rating
        3. 7.3.1.3 Full-Scale Current Rating
      2. 7.3.2  PWM Motor Drivers
      3. 7.3.3  Microstepping Indexer
      4. 7.3.4  Current Regulation
      5. 7.3.5  Controlling RREF With an MCU DAC
        1. 7.3.5.1 Various Sources of Error
          1. 7.3.5.1.1 VRREF, ARREF, and RREF Error
          2. 7.3.5.1.2 VDAC Error
        2. 7.3.5.2 Application-Specific Error Calculations
      6. 7.3.6  Decay Modes
        1. 7.3.6.1 Mode 1: Slow Decay for Increasing and Decreasing Current
        2. 7.3.6.2 Mode 2: Slow Decay for Increasing Current, Mixed Decay for Decreasing Current
        3. 7.3.6.3 Mode 3: Mixed Decay for Increasing and Decreasing Current
      7. 7.3.7  Blanking Time
      8. 7.3.8  Charge Pump
      9. 7.3.9  LDO Voltage Regulator
      10. 7.3.10 Logic and Multi-Level Pin Diagrams
      11. 7.3.11 Protection Circuits
        1. 7.3.11.1 VM UVLO
        2. 7.3.11.2 VCP Undervoltage Lockout (CPUV)
        3. 7.3.11.3 Overcurrent Protection (OCP)
        4. 7.3.11.4 Thermal Shutdown (TSD)
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Stepper Motor Speed
        2. 8.2.2.2 Current Regulation
        3. 8.2.2.3 Decay Modes
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
    1. 9.1 Bulk Capacitance
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.3 Microstepping Indexer

Built-in indexer logic in the DRV8884 allows a number of different stepping configurations. The Mx pins are used to configure the stepping format as shown in Table 2.

Table 2. Microstepping Settings

M1 M0 STEP MODE
0 0 Full step (2-phase excitation) with 71% current
0 1 1/16 step
1 0 1/2 step
1 1 1/4 step
0 Z 1/8 step
1 Z Non-circular 1/2 step

Table 3 shows the relative current and step directions for full-step through 1/16-step operation. The AOUT current is the sine of the electrical angle; BOUT current is the cosine of the electrical angle. Positive current is defined as current flowing from xOUT1 to xOUT2 while driving.

At each rising edge of the STEP input the indexer travels to the next state in the table (see Table 3). The direction is shown with the DIR pin logic high. If the DIR pin is logic low, the sequence is reversed.

On power-up or when exiting sleep mode, keep the STEP pin logic low, otherwise the indexer will advance one step.

Note that if the step mode is changed from full, 1/2, 1/4, 1/8, or 1/16 to full, 1/2, 1/4, 1/8, or 1/16 while stepping, the indexer will advance to the next valid state for the new MODE setting at the rising edge of STEP. If the step mode is changed from or to non-circular 1/2 step, the indexer will immediately go to the valid state for that mode.

The home state is an electrical angle of 45°. This state is entered after power-up, after exiting logic undervoltage lockout (UVLO), or after exiting sleep mode. Table 3 shows this state with the cells outlined in red.

Table 3. Microstepping Relative Current per Step (DIR = 1)

FULL STEP 1/2 STEP 1/4 STEP 1/8 STEP 1/16 STEP ELECTRICAL ANGLE (DEGREES) AOUT CURRENT (% FULL-SCALE) BOUT CURRENT (% FULL-SCALE)
1 1 1 1 0.000° 0% 100%
2 5.625° 10% 100%
2 3 11.250° 20% 98%
4 16.875° 29% 96%
2 3 5 22.500° 38% 92%
6 28.125° 47% 88%
4 7 33.750° 56% 83%
8 39.375° 63% 77%
1 2 3 5 9 45.000° 71% 71%
10 50.625° 77% 63%
6 11 56.250° 83% 56%
12 61.875° 88% 47%
4 7 13 67.500° 92% 38%
14 73.125° 96% 29%
8 15 78.750° 98% 20%
16 84.375° 100% 10%
3 5 9 17 90.000° 100% 0%
18 95.625° 100% –10%
10 19 101.250° 98% –20%
20 106.875° 96% –29%
6 11 21 112.500° 92% –38%
22 118.125° 88% –47%
12 23 123.750° 83% –56%
24 129.375° 77% –63%
2 4 7 13 25 135.000° 71% –71%
26 140.625° 63% –77%
14 27 146.250° 56% –83%
28 151.875° 47% –88%
8 15 29 157.500° 38% –92%
30 163.125° 29% –96%
16 31 168.750° 20% –98%
32 174.375° 10% –100%
5 9 17 33 180.000° 0% –100%
34 185.625° –10% –100%
18 35 191.250° –20% –98%
36 196.875° –29% –96%
10 19 37 202.500° –38% –92%
38 208.125° –47% –88%
20 39 213.750° –56% –83%
40 219.375° –63% –77%
3 6 11 21 41 225.000° –71% –71%
42 230.625° –77% –63%
22 43 236.250° –83% –56%
44 241.875° –88% –47%
12 23 45 247.500° –92% –38%
46 253.125° –96% –29%
24 47 258.750° –98% –20%
48 264.375° –100% –10%
7 13 25 49 270.000° –100% 0%
50 275.625° –100% 10%
26 51 281.250° –98% 20%
52 286.875° –96% 29%
14 27 53 292.500° –92% 38%
54 298.125° –88% 47%
28 55 303.750° –83% 56%
56 309.375° –77% 63%
4 8 15 29 57 315.000° –71% 71%
58 320.625° –63% 77%
30 59 326.250° –56% 83%
60 331.875° –47% 88%
16 31 61 337.500° –38% 92%
62 343.125° –29% 96%
32 63 348.750° –20% 98%
64 354.375° –10% 100%
1 1 1 1 360.000° 0% 100%

Non-circular 1/2–step operation is shown in Table 4. This stepping mode consumes more power than circular 1/2-step operation, but provides a higher torque at high motor rpm.

Table 4. Non-Circular 1/2-Stepping Current

NON-CIRCULAR 1/2 STEP AOUT CURRENT
(% FULL-SCALE)		 BOUT CURRENT
(% FULL-SCALE)		 ELECTRICAL ANGLE (°)
1 0 100 0
2 100 100 45
3 100 0 90
4 100 –100 135
5 0 –100 180
6 –100 –100 225
7 –100 0 270
8 –100 100 315