Technical Note

11/21

www.rohm.com

2010.11- Rev.A

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

BD3010AFV-M

0V

13.5V

3V

5V

1.25V

4.0V

4.0V

0V

0V

0V

0V

4.32V

4.25V VHS 70mV

CT pull up voltage

5V

OUT Voltage

0V

0mA

Reset on

OUT

Vcc

Ro

Io

INH

CT

CLK

4.0V

Power on reset

Reset on

Reset on

Power on

reset

●

Power ON Reset

Power ON reset (output delay time) is adjustable by CT pin capacitor.

TdLH(S) ≒(1.15V×CT capacitance(µF) / Ictc(µA)(TYP.)

・

TdLH

: Output delay time( power ON reset)

・

1.15V

: Upper switching threshold voltage(TYP.)

・

CT capacitance : Capacitor connected to CT pin

・

Ictc

: WDT charge current

＜

Calculation example＞with 0.01µF CT pin capacitor

TdLH(S) = 1.15V×0.01µF / 5.0µA

≒

2.3msec

※

If the CT capacitance is not the same as the condition on the electrical characteristics table, i.e., 0.01µF, choose the

capacitance value in ratio referring to the above equation.

＜

Timing Chart＞ ※Watchdog Timer OFF(INH ON)