4.10 External Power On Reset Circuit
The circuit shown in Fig.16 implements an external RC to produce the reset pulse. The pulse width
(time constant) should be kept long enough for Vdd to reached minimum operation voltage. This circuit
is used when the power supply has slow rise time. Because the current leakage from the /RESET pin is
±5µA, it is recommended that R should not be greater than 40 K. In this way, the /RESET pin
voltage is held below 0.2V. The diode (D) acts as a short circuit at the moment of power down. The
capacitor C will discharge rapidly and fully. Rin, the current-limited resistor, will prevent high current or
ESD (electrostatic discharge) from flowing to pin /RESET.
Fig. 13 External Power-Up Reset Circuit
This specification is subject to change without prior notice.