HD6432142 datasheet(675/1177 Pages) RENESAS

Il numero della parte	HD6432142

Spiegazioni elettronici	Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2100 Series

PDF	1177 Pages

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Produttore elettronici	RENESAS [Renesas Technology Corp]

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Section 20 A/D Converter

Rev. 4.00 Sep 27, 2006 page 631 of 1130

REJ09B0327-0400

Also, the bypass capacitors connected to AVCC, AVref and the filter capacitor connected to AN0

to AN7 must be connected to AVSS.

If a filter capacitor is connected as shown in figure 20.7, the input currents at the analog input pins

(AN0 to AN7) are averaged, and so an error may arise. Also, when A/D conversion is performed

frequently, as in scan mode, if the current charged and discharged by the capacitance of the

sample-and-hold circuit in the A/D converter exceeds the current input via the input impedance

in), an error will arise in the analog input pin voltage. Careful consideration is therefore required

when deciding the circuit constants.

AVCC

AVref

AN0 to AN7

AVSS

Notes:

Figures are reference values.

2. Rin: Input impedance

Rin*2

100

Ω

0.1 µF

0.01 µF

10 µF

Figure 20.7 Example of Analog Input Protection Circuit

Table 20.5

Analog Pin Ratings

Item

Min

Max

Unit

Analog input capacitance

—

Permissible signal source impedance

—

10*

Ω

Note:

When V

CC = 4.0 to 5.5 V and φ ≤ 12 MHz.

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