The DRV8860 is designed to operate from an input voltage supply (VM) range between 8 and 38 V. A 0.1-µF ceramic capacitor rated for VM must be placed as close as possible to the VM pin. In addition to the local decoupling cap, additional bulk capacitance is required and must be sized accordingly to the application requirements.

Bulk capacitance sizing is an important factor in motor drive system design. It is dependent on a variety of factors including:

• Type of power supply
• Acceptable supply voltage ripple
• Parasitic inductance in the power supply wiring
• Type of load
• Load startup current

The inductance between the power supply and motor drive system will limit the rate current can change from the power supply. If the local bulk capacitance is too small, the system will respond to excessive current demands or dumps from the motor with a change in voltage. The user should size the bulk capacitance to meet acceptable voltage ripple levels.

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

Figure 36. Example Setup of Motor Drive System with External Power Supply

10.1 Power Supply and Logic Sequencing

There is no specific sequence for powering-up the DRV8860. It is okay for digital input signals to be present before VM is applied. After VM is applied to the DRV8860, it begins operation based on the status of the control pins.