SMBP2501BPB datasheet(43/107 Pages) SONIX

43 / 107 page

SN8P2501B

8-Bit Micro-Controller

SONiX TECHNOLOGY CO., LTD

Page 43

Version 2.1

3.6.2 Diode & RC Reset Circuit

MCU

VDD

VSS

VCC

GND

RST

47K ohm

0.1uF

DIODE

100 ohm

This is the better reset circuit. The R1 and C1 circuit operation is like the simply reset circuit to make a power on signal.

The reset circuit has a simply protection against unusual power. The diode offers a power positive path to conduct

higher power to VDD. It is can make reset pin voltage level to synchronize with VDD voltage. The structure can

improve slight brown out reset condition.



Note: The R2 100 ohm resistor of “Simply reset circuit” and “Diode & RC reset circuit” is necessary to

limit any current flowing into reset pin from external capacitor C in the event of reset pin breakdown due

to Electrostatic Discharge (ESD) or Electrical Over-stress (EOS).

3.6.3 Zener Diode Reset Circuit

MCU

VDD

VSS

VCC

GND

RST

33K ohm

40K ohm

10K ohm

The zener diode reset circuit is a simple low voltage detector and can improve brown out reset condition

completely

. Use zener voltage to be the active level. When VDD voltage level is above “Vz + 0.7V”, the C terminal of

the PNP transistor outputs high voltage and MCU

operates normally. When VDD is below “Vz + 0.7V”, the C terminal of

the PNP transistor outputs low voltage and MCU is in reset mode. Decide the reset detect voltage by zener

specification. Select the right zener voltage to conform the application.

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