Datasheet

PIC16C62X
DS30235J-page 54  2003 Microchip Technology Inc.
FIGURE 9-11: EXTERNAL POWER-ON
RESET CIRCUIT (FOR
SLOW V
DD POWER-UP)
FIGURE 9-12: EXTERNAL BROWN-OUT
PROTECTION CIRCUIT 1
FIGURE 9-13: EXTERNAL BROWN-OUT
PROTECTION CIRCUIT 2
FIGURE 9-14: EXTERNAL BROWN-OUT
PROTECTION CIRCUIT 3
Note 1: External Power-on Reset circuit is
required only if V
DD power-up slope is
too slow. The diode D helps discharge
the capacitor quickly when V
DD powers
down.
2: < 40 kΩ is recommended to make sure
that voltage drop across R does not
violate the device’s electrical specifica-
tion.
3: R1 = 100Ω to 1 kΩ will limit any current
flowing into MCLR
from external capaci-
tor C in the event of MCLR/
VPP pin
breakdown due to Electrostatic
Discharge (ESD) or Electrical Over-
stress (EOS).
C
R1
R
D
V
DD
MCLR
PIC16C62X
VDD
Note 1: This circuit will activate RESET when
V
DD goes below (Vz + 0.7V) where
Vz = Zener voltage.
2: Internal Brown-out Reset circuitry should
be disabled when using this circuit.
VDD
33k
10k
40k
V
DD
MCLR
PIC16C62X
Note 1: This brown-out circuit is less expen-
sive, albeit less accurate. Transistor
Q1 turns off when V
DD is below a
certain level such that:
2: Internal Brown-out Reset should be
disabled when using this circuit.
3: Resistors should be adjusted for the
characteristics of the transistor.
VDD x
R1
R1 + R2
= 0.7V
VDD
R2
40k
V
DD
MCLR
PIC16C62X
R1
Q1
This brown-out protection circuit employs
Microchip Technology’s MCP809 microcontroller
supervisor. The MCP8XX and MCP1XX families
of supervisors provide push-pull and open
collector outputs with both high and low active
RESET pins. There are 7 different trip point
selections to accommodate 5V and 3V systems.
MCLR
PIC16C62X
V
DD
Vss
RST
MCP809
VDD
bypass
capacitor
VDD