SH7041A datasheet(622/923 Pages) RENESAS

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16.7

Usage Notes

The following points should be noted when using the mid-speed A/D converter.

16.7.1

Analog Voltage Settings

(1) Analog input voltage range

The voltage applied to analog input pins during A/D conversion should be in the range AVSS

≤ ANn ≤ AV

ref (n = 0 to 7).

(2) AV

CC and AVSS input voltages

For the AV

CC and AVSS input voltages, set AVCC = VCC ±10% and AVSS = VSS. When the

medium-speed A/D converter is not used, set AV

CC = VCC and AVSS = VSS.

(3) AVref input voltage

For the AV

ref pin input voltage analog reference, set AVref ≤ AVCC. When the medium-speed

A/D converter is not used, set AV

ref = AVCC.

(4) AV

CC and AVref must be connected to the power supply (VCC) even if the medium-speed A/D

converter is not used or is in standby mode.

16.7.2

Handling of Analog Input Pins

To prevent damage from surges and other abnormal voltages at the analog input pins (AN0-AN7),

connect a protection circuit such as that shown in figure 16.8. This circuit also includes a CR filter

function that suppresses error due to noise. The circuit shown here is only a design example;

circuit constants must be decided on the basis of the actual operating conditions.

Figure 16.9 shows an equivalent circuit for the analog input pins, and table 16.6 summarizes the

analog input pin specifications.

SH7041A Datasheet(PDF) 622 Page - Renesas Technology Corp