SLVSFN2B September   2021  – February 2022 DRV8311

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 SPI Timing Requirements
    7. 7.7 SPI Secondary Device Mode Timings
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Output Stage
      2. 8.3.2  Control Modes
        1. 8.3.2.1 6x PWM Mode (DRV8311S and DRV8311H variants only)
        2. 8.3.2.2 3x PWM Mode (DRV8311S and DRV8311H variants only)
        3. 8.3.2.3 PWM Generation Mode (DRV8311S and DRV8311P Variants)
      3. 8.3.3  Device Interface Modes
        1. 8.3.3.1 Serial Peripheral Interface (SPI)
        2. 8.3.3.2 Hardware Interface
      4. 8.3.4  AVDD Linear Voltage Regulator
      5. 8.3.5  Charge Pump
      6. 8.3.6  Slew Rate Control
      7. 8.3.7  Cross Conduction (Dead Time)
      8. 8.3.8  Propagation Delay
      9. 8.3.9  Pin Diagrams
        1. 8.3.9.1 Logic Level Input Pin (Internal Pulldown)
        2. 8.3.9.2 Logic Level Input Pin (Internal Pullup)
        3. 8.3.9.3 Open Drain Pin
        4. 8.3.9.4 Push Pull Pin
        5. 8.3.9.5 Four Level Input Pin
      10. 8.3.10 Current Sense Amplifiers
        1. 8.3.10.1 Current Sense Amplifier Operation
        2. 8.3.10.2 Current Sense Amplifier Offset Correction
      11. 8.3.11 Protections
        1. 8.3.11.1 VM Supply Undervoltage Lockout (NPOR)
        2. 8.3.11.2 Under Voltage Protections (UVP)
        3. 8.3.11.3 Overcurrent Protection (OCP)
          1. 8.3.11.3.1 OCP Latched Shutdown (OCP_MODE = 010b)
          2. 8.3.11.3.2 OCP Automatic Retry (OCP_MODE = 000b or 001b)
          3. 8.3.11.3.3 OCP Report Only (OCP_MODE = 011b)
          4. 8.3.11.3.4 OCP Disabled (OCP_MODE = 111b)
        4. 8.3.11.4 Thermal Protections
          1. 8.3.11.4.1 Thermal Warning (OTW)
          2. 8.3.11.4.2 Thermal Shutdown (OTSD)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Functional Modes
        1. 8.4.1.1 Sleep Mode
        2. 8.4.1.2 Operating Mode
        3. 8.4.1.3 Fault Reset (CLR_FLT or nSLEEP Reset Pulse)
    5. 8.5 SPI Communication
      1. 8.5.1 Programming
        1. 8.5.1.1 SPI and tSPI Format
  9. 9 DRV8311 Registers
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 Three-Phase Brushless-DC Motor Control
        1. 10.2.1.1 Detailed Design Procedure
          1. 10.2.1.1.1 Motor Voltage
        2. 10.2.1.2 Driver Propagation Delay and Dead Time
        3. 10.2.1.3 Delay Compensation
        4. 10.2.1.4 Current Sensing and Output Filtering
        5. 10.2.1.5 Application Curves
    3. 10.3 Three Phase Brushless-DC tSPI Motor Control
      1. 10.3.1 Detailed Design Procedure
    4. 10.4 Alternate Applications
  11. 11Power Supply Recommendations
    1. 11.1 Bulk Capacitance
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Thermal Considerations
      1. 12.3.1 Power Dissipation and Junction Temperature Estimation
  13. 13Device and Documentation Support
    1. 13.1 Support Resources
    2. 13.2 Trademarks
    3. 13.3 Electrostatic Discharge Caution
    4. 13.4 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

12.3.1 Power Dissipation and Junction Temperature Estimation

Power Dissipation

The power loss in DRV8311 include standby power losses, LDO power losses, FET conduction and switching losses, and diode losses. The FET conduction loss dominates the total power dissipation in DRV8311. At start-up and fault conditions, the output current is much higher than normal current; remember to take these peak currents and their duration into consideration. The total device dissipation is the power dissipated in each of the three half bridges added together. The maximum amount of power that the device can dissipate depends on ambient temperature and heatsinking. Note that RDS,ON increases with temperature, so as the device heats, the power dissipation increases. Take this into consideration when designing the PCB and heatsinking.

A summary of equations for calculating each loss is listed in Table 12-1 for trapezoidal control and field-oriented control.

Table 12-1 DRV8311 Power Losses for Trapezoidal and Field-oriented Control
Loss typeTrapezoidal controlField-oriented control
Standby powerPstandby = VVM x IVM_TA
LDO (from VM)PLDO = (VVIN_AVDD - VAVDD) x IAVDD
FET conductionPCON = 2 x (IPK(trap))2 x RDS,ON(TA)PCON = 3 x (IRMS(FOC))2 x RDS,ON(TA)
FET switchingPSW = IPK(trap) x VPK(trap) x trise/fall x fPWM PSW = 3 x IRMS(FOC) x VPK(FOC) x trise/fall x fPWM
Diode (dead time)Pdiode = 2 x IPK(trap) x VF(diode) x tDEAD x fPWMPdiode = 6 x IRMS(FOC) x VF(diode) x tDEAD x fPWM

Junction Temperature Estimation

To calculate the junction temperature of the die from power losses, use Equation 17. Note that the thermal resistance RθJA depends on PCB configurations such as the ambient temperature, numbers of PCB layers, copper thickness, and the PCB size.

Equation 17. TJ℃=PLOSSW×RθJA℃/W+TA℃

Refer BLDC integrated MOSFET thermal calculator for estimating the approximate device power dissipation and junction temperature at different use cases.