PIC16F628-20P Datasheet, PDF (102/170 Pages) Microchip Technology – FLASH-Based 8-Bit CMOS Microcontroller

PIC16F62X
FIGURE 14-11:
VDD
VDD
EXTERNAL POWER-ON
RESET CIRCUIT (FOR
SLOW VDD POWER-UP)
D
R
R1
MCLR
C
PIC16F62X
Note 1: External Power-on Reset circuit is required
only if VDD power-up slope is too slow. The
diode D helps discharge the capacitor
quickly when VDD powers down.
2: R < 40 kΩ is recommended to make sure
that voltage drop across R does not violate
the device’s electrical specification.
3: R1 = 100Ω to 1 kΩ will limit any current
flowing into MCLR from external capacitor
C in the event of MCLR/VPP pin breakdown
due to Electrostatic Discharge (ESD) or
Electrical Overstress (EOS).
FIGURE 14-12:
VDD
33k
EXTERNAL BROWN-OUT
PROTECTION CIRCUIT 1
VDD
10k
MCLR
40k _PIC16F62X
Note 1: This circuit will activate RESET when VDD
goes below (Vz + 0.7V) where Vz = Zener
voltage.
2: Internal Brown-out Detect Reset circuitry
should be disabled when using this circuit.
FIGURE 14-13:
VDD
R1
R2
EXTERNAL BROWN-OUT
PROTECTION CIRCUIT 2
VDD
Q1
MCLR
40k _PIC16F62X
Note 1: This Brown-out Circuit is less expensive, albeit
less accurate. Transistor Q1 turns off when VDD is
below a certain level such that:
R1
VDD x
= 0.7V
R1 + R2
2: Idnistearbnl_Vaeld_dB_dwrohxwenn-uosuitn_RDg₁ethteisctcRirc₌eusiet_0.t.s₇h_Vould be
3: Resistors shouldRb1e+adRju2sted for the
characteristics of the transistor.
DS40300C-page 100
Preliminary
 2003 Microchip Technology Inc.