SLVSH86A December   2023  – June 2024 MCT8314Z

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 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 SPI Timing Requirements
    7. 6.7 SPI Secondary Device Mode Timings
    8. 6.8 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Output Stage
      2. 7.3.2  PWM Control Mode (1x PWM Mode)
        1. 7.3.2.1 Analog Hall Input Configuration
        2. 7.3.2.2 Digital Hall Input Configuration
        3. 7.3.2.3 Asynchronous Modulation
        4. 7.3.2.4 Synchronous Modulation
        5. 7.3.2.5 Motor Operation
      3. 7.3.3  Device Interface Modes
        1. 7.3.3.1 Serial Peripheral Interface (SPI)
        2. 7.3.3.2 Hardware Interface
      4. 7.3.4  AVDD Linear Voltage Regulator
      5. 7.3.5  Charge Pump
      6. 7.3.6  Slew Rate
      7. 7.3.7  Cross Conduction (Dead Time)
      8. 7.3.8  Propagation Delay
      9. 7.3.9  Pin Diagrams
        1. 7.3.9.1 Logic Level Input Pin (Internal Pulldown)
        2. 7.3.9.2 Logic Level Input Pin (Internal Pullup)
        3. 7.3.9.3 Open Drain Pin
        4. 7.3.9.4 Push Pull Pin
        5. 7.3.9.5 Seven Level Input Pin
      10. 7.3.10 Automatic Synchronous Rectification Mode (ASR Mode)
      11. 7.3.11 Cycle-by-Cycle Current Limit
        1. 7.3.11.1 Cycle by Cycle Current Limit with 100% Duty Cycle Input
      12. 7.3.12 Hall Comparators (Analog Hall Inputs)
      13. 7.3.13 Advance Angle
      14. 7.3.14 FG Signal
      15. 7.3.15 Protections
        1. 7.3.15.1 VM Supply Undervoltage Lockout (NPOR)
        2. 7.3.15.2 AVDD Undervoltage Lockout (AVDD_UV)
        3. 7.3.15.3 VCP Charge Pump Undervoltage Lockout (CPUV)
        4. 7.3.15.4 Overvoltage Protections (OVP)
        5. 7.3.15.5 Overcurrent Protection (OCP)
          1. 7.3.15.5.1 OCP Latched Shutdown (OCP_MODE = 00b or MCT8314ZH)
          2. 7.3.15.5.2 OCP Automatic Retry (OCP_MODE = 01b)
          3. 7.3.15.5.3 OCP Report Only (OCP_MODE = 10b)
          4. 7.3.15.5.4 OCP Disabled (OCP_MODE = 11b)
        6. 7.3.15.6 Motor Lock (MTR_LOCK)
          1. 7.3.15.6.1 MTR_LOCK Latched Shutdown (MTR_LOCK_MODE = 00b)
          2. 7.3.15.6.2 MTR_LOCK Automatic Retry (MTR_LOCK_MODE = 01b or MCT8314ZH)
          3. 7.3.15.6.3 MTR_LOCK Report Only (MTR_LOCK_MODE= 10b)
          4. 7.3.15.6.4 MTR_LOCK Disabled (MTR_LOCK_MODE = 11b)
        7. 7.3.15.7 Thermal Warning (OTW)
        8. 7.3.15.8 Thermal Shutdown (OTS)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Functional Modes
        1. 7.4.1.1 Sleep Mode
        2. 7.4.1.2 Operating Mode
        3. 7.4.1.3 Fault Reset (CLR_FLT or nSLEEP Reset Pulse)
    5. 7.5 SPI Communication
      1. 7.5.1 Programming
        1. 7.5.1.1 SPI Format
  9. 8 Register Map
    1. 8.1 STATUS Registers
    2. 8.2 CONTROL Registers
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Hall Sensor Configuration and Connection
      1. 9.2.1 Typical Configuration
      2. 9.2.2 Open Drain Configuration
      3. 9.2.3 Series Configuration
      4. 9.2.4 Parallel Configuration
    3. 9.3 Typical Applications
      1. 9.3.1 Three-Phase Brushless-DC Motor Control With Current Limit
        1. 9.3.1.1 Detailed Design Procedure
          1. 9.3.1.1.1 Motor Voltage
          2. 9.3.1.1.2 Using Automatic Synchronous Rectification Mode (ASR Mode)
          3. 9.3.1.1.3 Power Dissipation and Junction Temperature Losses
        2. 9.3.1.2 Application Curves
    4. 9.4 Power Supply Recommendations
      1. 9.4.1 Bulk Capacitance
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
      3. 9.5.3 Thermal Considerations
        1. 9.5.3.1 Power Dissipation
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Package Option Addendum
    2. 12.2 Tape and Reel Information

Package Options

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

9.4.1 Bulk Capacitance

Having an appropriate local bulk capacitance is an important factor in motor drive system design. It is generally beneficial to have more bulk capacitance, while the disadvantages are increased cost and physical size.

The amount of local capacitance needed depends on a variety of factors, including:

  • The highest current required by the motor system
  • The capacitance and current capability of the power supply
  • The amount of parasitic inductance between the power supply and motor system
  • The acceptable voltage ripple
  • The type of motor used (brushed dc, brushless DC, stepper)
  • The motor braking method

The inductance between the power supply and the motor drive system limits the rate current can change from the power supply. If the local bulk capacitance is too small, the system responds to excessive current demands or dumps from the motor with a change in voltage. When adequate bulk capacitance is used, the motor voltage remains stable and high current can be quickly supplied.

The data sheet generally provides a recommended value, but system-level testing is required to determine the appropriate sized bulk capacitor.

MCT8314Z Example Setup of Motor Drive System With External Power SupplyFigure 9-15 Example Setup of Motor Drive System With External Power Supply

The voltage rating for bulk capacitors should be higher than the operating voltage, to provide margin for cases when the motor transfers energy to the supply.