Technical Note

5/7

BD47

□□G series

www.rohm.com

2010.04 - Rev.C

© 2010 ROHM Co., Ltd. All rights reserved.

 Circuit Applications

1)

The following is an example of an application circuit using Reset IC for normal power supply detection. BD47

□□G

series requires a pull up resistor on the output terminal. The pull up resister value should be decided. As the

application with enough confirmation of power supply level and output current capability. When a capacitor has been

inserted into the output terminal to delay the output time or to remove noise, the output will be slower during starting or

stopping. Please be careful to select the appropriate pull up resistors, output current and capacitor when inserting a

bypass capacitor between input and GND. Please be aware that if an extremely large capacitor is used, the response

time will become excessively slow.

2)

The following shows an example of adding delay time to a reset signal. It is possible to set the delay time using the

capacitor CL and the resistor RL connected to the output terminal as shown below. At VCC start up, CL will be

charged by RL. The CL and RL time constants and the threshold voltage of the Reset terminal determine the charge

delay time. When VCC is decreased, CL is discharged through the Reset IC. The sum of the respective times plus the

delay time of the IC itself becomes the reset signal delay time.

Fig.12

Vref

GND

5

4

3

BD47□□G

Reset Pin

microcontroller

●●●●●●●●●●●●

●●●●●●●●●●●●

●●●

●●●

●●●●

●

GND

BD47□□G

RESET

GND

CPU

Micro-controller

0V

RESET

Fig.13