RX610 Group
23. A/D Converter
R01UH0032EJ0120 Rev.1.20
Page 805 of 1006
Feb 20, 2013
23.6.10
Realizing High-Speed Conversion
To realize high-speed conversion, connect external 0.1-μF capacitors between the analog input pins (AN0 to AN15) and
V
REFL
. This is shown in figure 23.18. However, to prevent the impedance of the signal source due to the input capacitance
of the sample-and-hold circuit of the A/D converter from affecting the conversion time, the externally connected
capacitors must be fully charged before the start of conversion.
Furthermore, when the voltages on the analog input pins fluctuate due to scanning and so on, so describing renewal of the
charge of the externally connected capacitors, high-speed conversion is not realized.
Rin
*
2
AVCC
VREFH
AN0 to AN15
AVSS
*
1
*
1
VREFL
0.1
µ
F
0.1
µ
F
0.1
µ
F
The value in parentheses indicates the pin number.
1. The value is for reference.
2. Rin: Input impedance
Notes:
10
µ
F
0.01
µ
F
Figure 23.18 Example of an Externally Connected Capacitor for High-Speed Conversion
Summary of Contents for RX600 Series
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