SLLSFU1A December 2023 – July 2024 MCF8315C
PRODMIX
A 3.3V linear regulator is integrated into MCF8315C and is available for use by external circuitry. This AVDD LDO regulator is used for powering up the internal circuitry of the device and additionally, this regulator can also provide the supply voltage for a low-power MCU or other external circuitry supporting up to 20mA. The output of the AVDD regulator should be bypassed near the AVDD pin with an X5R or X7R, 1µF, 6.3V ceramic capacitor routed directly back to the adjacent AGND ground pin.
The AVDD nominal, no-load output voltage is 3.3V.
Use Equation 1 to calculate the power dissipated in the device by the AVDD linear regulator with VM as supply (BUCK_PS_DIS = 1b)
For example, at a VVM of 24-V, drawing 20-mA out of AVDD results in a power dissipation as shown in Equation 2.
Use Equation 3 to calculate the power dissipated in the device by the AVDD linear regulator with buck output as supply (BUCK_PS_DIS = 0b)
For example, at a VFB_BK of 5 V, drawing 20 mA out of AVDD results in a LDO power dissipation as shown in Equation 4.