When Not Using Internal Power Supply Step-Down Circuit; H8/3847S Group; Notes On Switching From The H8/3847R To The H8/38347 Or H8/38447; Figure 14.2 Power Supply Connection When Internal Step-Down Circuit Is Not Used - Renesas H8/3847R Series Hardware Manual

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Table of Contents

Section 14 Power Supply Circuit

When Not Using Internal Power Supply Step-Down Circuit

When the internal power supply step-down circuit is not used, connect the external power supply

directly to the internal power supply. The permissible range for the power supply voltage is 1.8 V

to 5.5 V for the H8/3847R Group and 2.7 V to 3.6 V for the H8/38347 Group and H8/38447

Group. Normally, however, the internal power supply step-down circuit should be used. Operation

cannot be guaranteed if a voltage outside this range is input.

The H8/3847S Group has two V

Examine the following with regard to the power supply circuit.

(1) If the internal power supply step-down circuit was used on the H8/3847R

The stabilization capacitance value differs between the products. It is necessary to change the

value from 0.1 µF (H8/3847R) to 0.33 µF (H8/38347 or H8/38447). Note that these values are

rough guidelines and it is still necessary to confirm system operation.

(2) If the internal power supply step-down circuit was not used on the H8/3847R

Use of the internal power supply step-down circuit of the H8/38347 or H8/38447 is

recommended. Furthermore, operation at a V

internal power supply step-down circuit is not used. It is therefore necessary to change the

connection to use the internal power supply step-down circuit.

Rev. 6.00 Aug 04, 2006 page 462 of 680

REJ09B0145-0600

pin, as shown in figure 14.2. The external power supply is then input

Step-down circuit

pins, which should be interconnected externally.

of 3.6 V or greater is not guaranteed if the