SLOSE48 December   2020 DRV8434A

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1. 5.1 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
      1. 6.6.1 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 Controlling VREF with an MCU DAC
      5. 7.3.5 Current Regulation and Decay Mode
        1. 7.3.5.1 Smart tune Ripple Control
        2. 7.3.5.2 Blanking Time
      6. 7.3.6 Charge Pump
      7. 7.3.7 Linear Voltage Regulators
      8. 7.3.8 Logic Level, tri-level and quad-level Pin Diagrams
        1. 7.3.8.1 nFAULT Pin
      9. 7.3.9 Protection Circuits
        1. 7.3.9.1 VM Undervoltage Lockout (UVLO)
        2. 7.3.9.2 VCP Undervoltage Lockout (CPUV)
        3. 7.3.9.3 Overcurrent Protection (OCP)
        4. 7.3.9.4 Stall Detection
        5. 7.3.9.5 Open-Load Detection (OL)
        6. 7.3.9.6 Thermal Shutdown (OTSD)
        7.       Fault Condition Summary
    4. 7.4 Device Functional Modes
      1. 7.4.1 Sleep Mode (nSLEEP = 0)
      2.      43
      3. 7.4.2 Disable Mode (nSLEEP = 1, ENABLE = 0)
      4. 7.4.3 Operating Mode (nSLEEP = 1, ENABLE = Hi-Z/1)
      5. 7.4.4 nSLEEP Reset Pulse
      6.      Functional Modes Summary
  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 Mode
        4. 8.2.2.4 Application Curves
        5. 8.2.2.5 Thermal Application
          1. 8.2.2.5.1 Power Dissipation
          2. 8.2.2.5.2 Conduction Loss
          3. 8.2.2.5.3 Switching Loss
          4. 8.2.2.5.4 Power Dissipation Due to Quiescent Current
          5. 8.2.2.5.5 Total Power Dissipation
          6. 8.2.2.5.6 Device Junction Temperature Estimation
  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 Receiving Notification of Documentation Updates
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 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 DRV8434A device allows a number of different step modes. The M0 and M1 pins are used to configure the step mode as shown in Table 7-2. The settings can be changed on the fly.

Table 7-2 Microstepping Indexer Settings
M0M1STEP MODE
0

0

Full step (2-phase excitation) with 100% current
0330 kΩ to GNDFull step (2-phase excitation) with 71% current
10Non-circular 1/2 step
Hi-Z01/2 step
011/4 step
111/8 step
Hi-Z11/16 step
0Hi-Z1/32 step
Hi-Z330kΩ to GND1/64 step
Hi-ZHi-Z1/128 step
1Hi-Z1/256 step

Table 7-3 shows the relative current and step directions for full-step (71% current), 1/2 step, 1/4 step and 1/8 step operation. Higher microstepping resolutions follow the same pattern. The AOUT current is the sine of the electrical angle and the BOUT current is the cosine of the electrical angle. Positive current is defined as current flowing from the xOUT1 pin to the xOUT2 pin while driving.

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

Note:

If the step mode is changed on the fly while stepping, the indexer advances to the next valid state for the new step mode setting at the rising edge of STEP.

The initial excitation state is an electrical angle of 45°, corresponding to 71% of full-scale current in both coils. This state is entered immediately after power-up, after exiting logic undervoltage lockout, or after exiting sleep mode.

Table 7-3 Relative Current and Step Directions
1/8 STEP1/4 STEP1/2 STEPFULL STEP 71%AOUT CURRENT
(% FULL-SCALE)		BOUT CURRENT
(% FULL-SCALE)		ELECTRICAL ANGLE (DEGREES)
1110%100%0.00
220%98%11.25
3238%92%22.50
456%83%33.75
532171%71%45.00
683%56%56.25
7492%38%67.50
898%20%78.75
953100%0%90.00
1098%-20%101.25
11692%-38%112.50
1283%-56%123.75
1374271%-71%135.00
1456%-83%146.25
15838%-92%157.50
1620%-98%168.75
17950%-100%180.00
18-20%-98%191.25
1910-38%-92%202.50
20-56%-83%213.75
211163-71%-71%225.00
22-83%-56%236.25
2312-92%-38%247.50
24-98%-20%258.75
25137-100%0%270.00
26-98%20%281.25
2714-92%38%292.50
28-83%56%303.75
291584-71%71%315.00
30-56%83%326.25
3116-38%92%337.50
32-20%98%348.75

Table 7-4 shows the full step operation with 100% full-scale current. This stepping mode consumes more power than full-step mode with 71% current, but provides a higher torque at high motor RPM.

Table 7-4 Full Step with 100% Current
FULL STEP 100%AOUT CURRENT
(% FULL-SCALE)		BOUT CURRENT
(% FULL-SCALE)		ELECTRICAL ANGLE (DEGREES)
110010045
2-100100135
3-100-100225
4100–100315

Table 7-5 shows the noncircular 1/2–step operation. This stepping mode consumes more power than circular 1/2-step operation, but provides a higher torque at high motor RPM.

Table 7-5 Non-Circular 1/2-Stepping Current
NON-CIRCULAR 1/2-STEPAOUT CURRENT
(% FULL-SCALE)		BOUT CURRENT
(% FULL-SCALE)		ELECTRICAL ANGLE (DEGREES)
101000
210010045
3100090
4100–100135
50–100180
6–100–100225
7–1000270
8–100100315