HD6413008VX25 Renesas Electronics America, HD6413008VX25 Datasheet - Page 478

• Manufacturer Part Number: HD6413008VX25
• Description: MCU 5V 0K 100-TQFP
• Manufacturer: Renesas Electronics America
• Series: H8® H8/300Hr

Specifications of HD6413008VX25

• Core Processor: H8/300H
• Core Size: 16-Bit
• Speed: 25MHz
• Connectivity: SCI, SmartCard
• Peripherals: PWM, WDT
• Number Of I /o: 35
• Program Memory Type: ROMless
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 3.6 V
• Data Converters: A/D 8x10b; D/A 2x8b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 75°C
• Package / Case: 100-TQFP, 100-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Program Memory Size: -
• Other names: HD6413008VTE25; HD6413008VTE25

14. A/D Converter
7. Allowable Signal-Source Impedance
8. Effect on Absolute Accuracy
Rev.4.00 Aug. 20, 2007 Page 432 of 638
REJ09B0395-0400
The analog inputs of the H8/3008 are designed to assure accurate conversion of input signals
with a signal-source impedance not exceeding 10 kΩ. The reason for this rating is that it
enables the input capacitor in the sample-and-hold circuit in the A/D converter to charge
within the sampling time. If the sensor output impedance exceeds 10 kΩ, charging may be
inadequate and the accuracy of A/D conversion cannot be guaranteed.
If a large external capacitor is provided in single mode, then the internal 10-kΩ input
resistance becomes the only significant load on the input. In this case the impedance of the
signal source is not a problem.
A large external capacitor, however, acts as a low-pass filter. This may make it impossible to
track analog signals with high dv/dt (e.g. a variation of 5 mV/μs) (figure 14.11). To convert
high-speed analog signals or to use scan mode, insert a low-impedance buffer.
Attaching an external capacitor creates a coupling with ground, so if there is noise on the
ground line, it may degrade absolute accuracy. The capacitor must be connected to an
electrically stable ground, such as AV
Figure 14.10 A/D Converter Accuracy Definitions (2)
Digital
output
characteristic
conversion
Ideal A/D
Offset error
Actual A/D conversion
characteristic
SS
.
Nonlinearity
error
Analog input
voltage
Full-scale
error
FS