UPD78F0034BGC-8BS-A Renesas Electronics America, UPD78F0034BGC-8BS-A Datasheet - Page 277

• Manufacturer Part Number: UPD78F0034BGC-8BS-A
• Description: MCU 8-Bit 78K0 CISC 32KB Flash 2.5V/3.3V/5V 64-Pin LQFP
• Manufacturer: Renesas Electronics America

Specifications of UPD78F0034BGC-8BS-A

• Package: 64LQFP
• Family Name: 78K0
• Maximum Speed: 12 MHz
• Ram Size: 1 KB
• Program Memory Size: 32 KB
• Operating Supply Voltage: 2.5|3.3|5 V
• Data Bus Width: 8 Bit
• Program Memory Type: Flash
• Number Of Programmable I/os: 51
• Interface Type: 3-Wire/UART
• On-chip Adc: 8-chx10-bit
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 3

(12) AV
(13) Internal equivalent circuit of ANI0 to ANI7 pins and permissible signal source impedance
Remark C1: 4.7 F to 10 F (reference value)
Remark n = 0 to 7
Connect a capacitor to the AV
has been stopped and then is started, the voltage applied to the AV
accuracy of the A/D conversion to drop. To prevent this, also connect a capacitor to the AV
Figure 13-18 shows an example of connecting a capacitor.
To complete sampling within the sampling time with sufficient A/D conversion accuracy, the impedance of the
signal source such as a sensor must be sufficiently low. Figure 13-19 shows the internal equivalent circuit of
the ANI0 to ANI7 pins.
If the impedance of the signal source is high, connect capacitors with a high capacitance to the pins ANI0 to ANI7.
An example of this is shown in Figure 13-20. In this case, however, the microcontroller cannot follow an analog
signal with a high differential coefficient because a lowpass filter is created.
To convert a high-speed analog signal or to convert an analog signal in the scan mode, insert a low-impedance
buffer.
REF
pin
C2: 0.01 F to 0.1 F (reference value)
Connect C2 as close to the pin as possible.
CHAPTER 13 8-BIT A/D CONVERTER ( PD780024A, 780024AY SUBSERIES)
Figure 13-19. Internal Equivalent Circuit of Pins ANI0 to ANI7
ANIn
Figure 13-18. Example of Connecting Capacitor to AV
C
1
REF
pin to minimize conversion errors due to noise. If an A/D conversion operation
C1
User’s Manual U14046EJ5V0UD
R1
C
2
C2
AV
AV
AV
Clamp using a diode with a low
V
F
DD
REF
SS
(0.3 V or lower).
R2
REF
pin becomes unstable, causing the
REF
Pin
C3
REF
pin.
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