HD64F2168VTE33 Renesas Electronics America, HD64F2168VTE33 Datasheet - Page 648

• Manufacturer Part Number: HD64F2168VTE33
• Manufacturer: Renesas Electronics America

Specifications of HD64F2168VTE33

• Cpu Family: H8S
• Device Core Size: 16/32Bit
• Frequency (max): 33MHz
• Interface Type: I2C/IrDA/SCI
• Program Memory Type: Flash
• Program Memory Size: 256KB
• Total Internal Ram Size: 40KB
• # I/os (max): 106
• Number Of Timers - General Purpose: 5
• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (max): 3.6V
• Operating Supply Voltage (min): 3V
• On-chip Adc: 8-chx10-bit
• On-chip Dac: 2-chx8-bit
• Instruction Set Architecture: CISC
• Operating Temp Range: -20C to 75C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 144
• Package Type: TQFP
• Lead Free Status / Rohs Status: Not Compliant

18.7
18.7.1
This LSI’s analog input is designed so that the conversion accuracy is guaranteed for an input
signal for which the signal source impedance is 5 kΩ or less. This specification is provided to
enable the A/D converter’s sample-and-hold circuit input capacitance to be charged within the
sampling time; if the sensor output impedance exceeds 10 kΩ, charging may be insufficient and it
may not be possible to guarantee the A/D conversion accuracy. However, if a large capacitance is
provided externally in single mode, the input load will essentially comprise only the internal input
resistance of 10 kΩ, and the signal source impedance is ignored. However, since a low-pass filter
effect is obtained in this case, it may not be possible to follow an analog signal with a large
differential coefficient (e.g., voltage fluctuation ratio of 5 mV/µs or greater) (see figure 18.6).
When converting a high-speed analog signal or converting in scan mode, a low-impedance buffer
should be inserted.
18.7.2
Adding capacitance results in coupling with GND, and therefore noise in GND may adversely
affect the absolute accuracy. Be sure to make the connection to an electrically stable GND such as
AVSS.
Care is also required to insure that filter circuits do not communicate with digital signals on the
mounting board, so acting as antennas.
Rev. 3.00, 03/04, page 606 of 830
Usage Notes
Permissible Signal Source Impedance
Influences on Absolute Accuracy
Sensor input
Sensor output
impedance
up to 5 kΩ
Low-pass
filter C
up to 0.1 µF
Figure 18.6 Example of Analog Input Circuit
This LSI
C
15 pF
in
=
A/D converter equivalent circuit
10 kΩ
20 pF