RX24U Datasheet, PDF (124/131 Pages) Renesas Technology Corp – 32-bit RXv2 CPU core

RX24U 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 5.59 and Figure 5.60 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
109
72
110
71
111
70
112
69
113
68
114
67
115
VSS 66
116
VSS 65
Bypass
capacitor
117
64
0.1 µF
118
VCC 63
119
62
120
61
121
60
122
59
123
124
RX24U Group
58
57
125
126
PLQP0144KA-B
56
55
127
128
(144-pin LFQFP)
54
53
129
130
(Top view)
52
51
131
50
132
49
133
48
134
47
135
46
136
45
137
44
138
139
VSS 43
VSS 42
Bypass
capacitor
140
41
0.1 µF
141
VCC 40
142
39
143
38
144
37
Bypass
capacitor
0.1 µF
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 5.59 Connecting Capacitors (144 Pins)
R01DS0278EJ0100 Rev.1.00
Mar 31, 2017
Page 124 of 131