SLVA505A February   2012  – July 2024 DRV8800 , DRV8801 , DRV8802 , DRV8803 , DRV8804 , DRV8805 , DRV8806 , DRV8811 , DRV8812 , DRV8813 , DRV8814 , DRV8818 , DRV8821 , DRV8823 , DRV8824 , DRV8828 , DRV8829 , DRV8830 , DRV8832 , DRV8832-Q1 , DRV8833 , DRV8834 , DRV8835 , DRV8836 , DRV8837 , DRV8840 , DRV8841 , DRV8842 , DRV8843 , DRV8844 , DRV8870 , DRV8871 , DRV8872

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Factors Limiting the Maximum Output Current of a Motor Driver
    1. 1.1 Thermal Limitations
    2. 1.2 Overcurrent Protection (OCP) Limitations
    3. 1.3 Silicon and Package Limitations
    4. 1.4 PCB Limitations and Thermal Management Techniques
      1. 1.4.1 Exposed Pad Packages
      2. 1.4.2 Continuous Copper Planes
      3. 1.4.3 Copper Thickness
      4. 1.4.4 Thermal Vias
      5. 1.4.5 Summary of Thermal Management Techniques
    5. 1.5 Thermal Estimations
  5. 2TI Motor Driver OCP Operation
  6. 3TI Motor Driver Data Sheet Ratings
    1. 3.1 Description
    2. 3.2 Absolute Maximum Ratings
    3. 3.3 Recommended Operating Conditions
    4. 3.4 Thermal Information
    5. 3.5 Electrical Characteristics
  7. 4References
  8. 5Revision History

3.1 Description

The description summary on page one of the data sheet, as well as information on ti.com, usually lists the recommended maximum output current for the device:

Features

  • Dual-H-Bridge Current-Control Motor Driver
    • Capable of Driving Two DC Motors or One Stepper Motor
    • Low MOSFET On-Resistance
  • Output Current 1.5-A RMS, 2-A Peak per H-Bridge (at VM = 5 V, 25°C)

These current specifications are based on thermal limitations as well as OCP current limitations.

In this case, the RMS (or DC) maximum current is calculated as the current that the device can provide at 25°C ambient temperature, when mounted on a standard JEDEC-specified PCB, before it enters overtemperature protection.

This current level is not attained at higher ambient temperatures, or on PCB layouts that are not as good at dissipating power as the standard JEDEC PCB. In the actual application, it may not be possible to drive this much current. To determine the actual maximum current in a specific application, calculations must be made that take the ambient temperature and PCB thermal resistance into account.

The peak current is limited by the OCP current threshold. The OCP current is specified in the Electrical Characteristics table. Exceeding this current does not damage the device, but can cause OCP to activate and disable the output.

In some cases, if the RDS(ON) of the FETs is low, the maximum peak and DC or RMS current levels can be identical. In this case, both peak and RMS/DC current is limited by the OCP current, not by thermals. At higher temperatures or on thermally poor PCB constructions, the maximum DC or RMS current decreases, as described above.