ZHCSR87 December 2022 DRV8316C
PRODUCTION DATA
In DRV8316C, the buck regulator components must be populated whether the buck is used or unused.
If unused, Resistor Mode should be configured by placing a small value resistor of 22-Ω for RBK and a 10-V rated, 22-μF capacitor for CBK- to minimize board space and reduce component cost. To disable the buck regulator, set the BUCK_DIS in the SPI variant. The buck cannot be disabled in the Hardware variant.
If the buck regulator is used, either the Inductor or Resistor Mode can be selected. Inductor Mode allows a 22-μH or 47-μH inductor be used for LBK. CBK- is recommended to be 22-μF. Ensure an appropriate inductor is chosen to allow for maximum peak saturation current at a 20% inductance drop since the buck can supply up to 600-mA external current.
Resistor Mode allows for power to be dissipated in an external resistor if the load requirement is less than 40-mA. Ensure the resistor is rated for the power dissipation required at worst case VM voltage dropout. See Equation 6, Equation 7, and Equation 8 to calculate the resistor power rating required for a 24-V rated system, 3.3V buck output voltage, and 20-mA load current.