SLVSF66A August   2019  – December  2019 DRV8874

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  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 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 External Components
      2. 7.3.2 Control Modes
        1. 7.3.2.1 PH/EN Control Mode (PMODE = Logic Low)
        2. 7.3.2.2 PWM Control Mode (PMODE = Logic High)
        3. 7.3.2.3 Independent Half-Bridge Control Mode (PMODE = Hi-Z)
      3. 7.3.3 Current Sense and Regulation
        1. 7.3.3.1 Current Sensing
        2. 7.3.3.2 Current Regulation
          1. 7.3.3.2.1 Fixed Off-Time Current Chopping
          2. 7.3.3.2.2 Cycle-By-Cycle Current Chopping
      4. 7.3.4 Protection Circuits
        1. 7.3.4.1 VM Supply Undervoltage Lockout (UVLO)
        2. 7.3.4.2 VCP Charge Pump Undervoltage Lockout (CPUV)
        3. 7.3.4.3 OUTx Overcurrent Protection (OCP)
        4. 7.3.4.4 Thermal Shutdown (TSD)
        5. 7.3.4.5 Fault Condition Summary
      5. 7.3.5 Pin Diagrams
        1. 7.3.5.1 Logic-Level Inputs
        2. 7.3.5.2 Tri-Level Inputs
        3. 7.3.5.3 Quad-Level Inputs
    4. 7.4 Device Functional Modes
      1. 7.4.1 Active Mode
      2. 7.4.2 Low-Power Sleep Mode
      3. 7.4.3 Fault Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Primary Application
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Current Sense and Regulation
          2. 8.2.1.2.2 Power Dissipation and Output Current Capability
          3. 8.2.1.2.3 Thermal Performance
            1. 8.2.1.2.3.1 Steady-State Thermal Performance
            2. 8.2.1.2.3.2 Transient Thermal Performance
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Alternative Application
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1 Current Sense and Regulation
        3. 8.2.2.3 Application Curves
  9. 9 Power Supply Recommendations
    1. 9.1 Bulk Capacitance
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
      1. 10.2.1 HTSSOP 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

8.2.1.2.3 Thermal Performance

The datasheet-specified junction-to-ambient thermal resistance, RθJA, is primarily useful for comparing various drivers or approximating thermal performance. However, the actual system performance may be better or worse than this value depending on PCB stackup, routing, number of vias, and copper area around the thermal pad. The length of time the driver drives a particular current will also impact power dissipation and thermal performance. This section considers how to design for steady-state and transient thermal conditions.

The data in this section was simulated using the following criteria:

  • 2-layer PCB, standard FR4, 1-oz (35 mm copper thickness) or 2-oz copper thickness.

  • Top layer: DRV887x HTSSOP package footprint and copper plane heatsink. Top layer copper area is varied in simulation.
  • Bottom layer: ground plane thermally connected through vias under the thermal pad for DRV887x. Bottom layer copper area varies with top copper area. Thermal vias are only present under the thermal pad (grid pattern with 1.2mm spacing).

  • 4-layer PCB, standard FR4. Outer planes are 1-oz (35 mm copper thickness) or 2-oz copper thickness.

  • Top layer: DRV887x HTSSOP package footprint and copper plane heatsink. Top layer copper area is varied in simulation. Inner planes were kept at 1-oz.
  • Mid layer 1: GND plane thermally connected to DRV887x thermal pad through vias. The area of the ground plane is 74.2 mm x 74.2 mm.
  • Mid layer 2: power plane, no thermal connection.
  • Bottom layer: signal layer with small copper pad underneath DRV887x and thermally connected through via stitching from the TOP and internal GND planes. Bottom layer thermal pad is the same size as the package (5 mm x 4.4 mm). Bottom pad size remains constant as top copper plane is varied. Thermal vias are only present under the thermal pad (grid pattern with 1.2mm spacing).

Figure 20 shows an example of the simulated board for the HTSSOP package. Table 9 shows the dimensions of the board that were varied for each simulation.

DRV8874 thermal_sim_pwp.gifFigure 20. HTSSOP PCB model top layer

Table 9. Dimension A for 16-pin PWP package

Cu area (mm2) Dimension A (mm)
2 16.43
4 22.35
8 30.68
16 42.42