R01UH0823EJ0100 Rev.1.00
Page 1816 of 1823
Jul 31, 2019
RX23W Group
51. Electrical Characteristics
51.16 Usage Notes
51.16.1
Connecting VCL Capacitor and Bypass Capacitors
This MCU integrates an internal voltage-down circuit, which is used for lowering the power supply voltage in the
internal MCU automatically to the optimum level. A 4.7-μF capacitor needs to be connected between this internal
voltage-down power supply (VCL pin) and the VSS pin. Place an external capacitor close to the pins. Do not apply the
power supply voltage to the VCL pin.
Insert a multilayer ceramic capacitor as a bypass capacitor between each pair of the power supply pins. Implement a
bypass capacitor as closer to the MCU power supply pins as possible. We recommend capacitors with a value of 2.2 µF
for that connected to the VCC_RF pin and 0.1 µF for the others. For the capacitors related to crystal oscillation, see
section 9, Clock Generation Circuit
. For the capacitors related to analog modules, also see
.
For notes on designing the printed circuit board, see the descriptions of the application note, the Hardware Design Guide
(R01AN1411EJ). The latest version can be downloaded from the Renesas Electronics website.