RX24T Datasheet, PDF (123/133 Pages) Renesas Technology Corp – 32-bit RXv2 CPU core

RX24T Group
5. Electrical Characteristics
5.12 Usage Notes
5.12.1 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 to adjust automatically to the optimum level. A 4.7-μF capacitor needs to be connected between this
internal voltage-down power supply (VCL pin) and VSS pin. Figure 5.61 to Figure 5.63 shows how to connect
external capacitors. 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 to the MCU power supply pins as close as possible. Use a recommended value of 0.1 μF as the
capacitance of the capacitors. For the capacitors related to crystal oscillation, see section 9, Clock Generation Circuit
in the User’s Manual: Hardware. For the capacitors related to analog modules, also see section 31, 12-Bit A/D
Converter (S12ADF) in the User’s Manual: Hardware.
For notes on designing the printed circuit board, see the descriptions of the application note “Hardware Design Guide”
(R01AN1411EJ). The latest version can be downloaded from Renesas Electronics Website.
Bypass
capacitor
0.1 µF
76
50
77
49
78
48
79
47
80
46
81
45
82
VSS 44
Bypass
83
43
capacitor
84
VCC 42
0.1 µF
85
RX24T Group
41
86
40
87
PLQP0100KB-B
39
88
89
(100-pin LFQFP)
38
37
90
91
(Top view)
36
35
92
34
93
33
94
32
95
VSS 31
Bypass
96
30
capacitor
97
VCC 29
0.1 µF
98
28
99
27
100
26
External capacitor
for power supply
stabilization
4.7 µF
Bypass
capacitor
0.1 µF
Note:
Do not apply the power supply voltage to the VCL pin.
Use a 4.7-µF multilayer ceramic for the VCL pin and place it close to the pin.
A recommended value is shown for the capacitance of the bypass
capacitors.
Figure 5.61 Connecting Capacitors (100 Pins)
R01DS0257EJ0200 Rev.2.00
Apr 14, 2017
Page 123 of 133