ZHCS276F September 2011 – February 2025 DRV8818
PRODUCTION DATA
- 1
- 1 特性
- 2 應用
- 3 說明
- 4 Pin Configuration and Functions
- 5 Specifications
- 6 Detailed Description
- 7 Application and Implementation
- 8 Device and Documentation Support
- 9 Revision History
- 10Mechanical, Packaging, and Orderable Information
封裝選項
機械數(shù)據(jù) (封裝 | 引腳)
- PWP|28
散熱焊盤機械數(shù)據(jù) (封裝 | 引腳)
- PWP|28
訂購信息
7.4.3.1 Power Dissipation
Power dissipation in the DRV8818 is dominated by the power dissipated in the output FET resistance, or RDS(ON). Average power dissipation when running a stepper motor can be roughly estimated by:
where
- PTOT is the total power dissipation.
- RDS(ON) is the resistance of each FET.
- IOUT(RMS) is the RMS output current being applied to each winding.
IOUT(RMS) is equal to the approximately 0.7x the full-scale output current setting. The factor of 4 comes from the fact that there are two motor windings, and at any instant two FETs are conducting winding current for each winding (one high-side and one low-side).
The maximum amount of power that can be dissipated in the DRV8818 is dependent on ambient temperature and heatsinking. The thermal dissipation ratings table in the data sheet can be used to estimate the temperature rise for typical PCB constructions.
Note that RDS(ON) increases with temperature, so as the device heats, the power dissipation increases. This must be taken into consideration when sizing the heatsink.