MCT8316Z datasheet(84/100 Pages) TI

84 / 100 page

9.3.1.1.3 Using Delay Compensation

Differences in delays of dead time and propagation delay can cause mismatch in the output timings of PWMs,

which can lead to duty cycle distortion. In order to accommodate differences in propagation delay between

various input conditions, the MCT8316Z-Q1 integrates a Delay Compensation feature.

Delay Compensation is used to match delay times for currents going into and out of phase by adding a variable

delay time (tvar) to match a preset target delay time. This delay time is configurable in SPI devices, and it is

recommended in the datasheets to choose a target delay time that is equal to the propagation delay time plus

the driver dead time (tpd + tdead).

For an example of Delay Compensation implementation, please visit the Delay and Dead Time in Integrated

MOSFET Drivers application note.

9.3.1.1.4 Using the Buck Regulator

In the MCT8316Z-Q1, 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-ohm for RBK and a 6.3-V

rated, 22-uF 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-uH or 47-uH inductor be used for LBK. CBK is recommended to be 22-uF. 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 5, Equation 6, and Equation 7 to calculate the resistor power rating required for a 24-V rated system,

3.3V buck output voltage, and 20-mA load current.

PRBK> VM−VBK ×IBK

(5)

PRBK> 24V−3.3V ×20mA

(6)

PR_BK>0.434W

(7)

9.3.1.1.5 Power Dissipation and Junction Temperature Losses

To calculate the junction temperature of the MCT8316Z-Q1 from power losses, use Equation 8. Note that the

thermal resistance θJA depends on PCB configurations such as the ambient temperature, numbers of PCB

layers, copper thickness on top and bottom layers, and the PCB area.

TJ℃ =PlossW × θJA℃W +TA℃

(8)

MCT8316Z-Q1

SLVSGO3 – DECEMBER 2021

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MCT8316Z Datasheet(PDF) 84 Page - Texas Instruments