EKTF6708 datasheet(137/158 Pages) EMC

137 / 158 page

eKTF6708

8-Bit Microcontroller

IC Product Specification (V1.2) 03.12.2020

 127

(This specification is subject to change without prior notice)

6.17 Power-On Considerations

Any microcontroller is not guaranteed to start to operate properly before the power supply

reaches its steady state. The eKTF6708 is equipped with a Power-on Voltage Detector

(POVD) with a detection level of 1.7V. It will work well if Vdd rises fast enough (50 ms or

less). However, in critical applications, extra devices are still required to assist in solving

power-up problems.

6.18 External Power-on Reset Circuit

The circuits diagram in Figure 6-15 implements an external RC to generate the reset pulse.

The pulse width (time constant) should be kept long enough for VDD to reach minimum

operational voltage. Apply this circuit when the power supply has slow rise time. Since the

current leakage from the /RESET pin is about

 5 A, it is recommended that R should not

be greater than 40KΩ in order for the /RESET pin voltage to remain at below 0.2V. The

diode (D) functions as a short circuit at the instant of power down. The capacitor (C) will

discharge rapidly and fully. The current-limited resistor (Rin) will prevent high current or

ESD (electrostatic discharge) from flowing into /RESET pin.

/RESET

VDD

Rin

Figure 6-15

External Power-Up Reset Circuit

EKTF6708 Datasheet(PDF) 137 Page - ELAN Microelectronics Corp