Attention to Internet Explorer users: ROHM website does not recommend browsing in IE 11. Please use latest browser to ensure the best performance on ROHM website.
In the datasheet for fixed delay time (built-in counter timer) type reset ICs, 'connect to ground if external reset by the ER pin is not used' is stated, but what are the concerns with leaving it open?
Since a pull-down resistor is built into the ER pin, it will operate even when open, but the resistance will be around 2MΩ. And because there is a possibility of malfunction due to substrate leakage or the effects of noise, we recommend shorting to ground when not in use.