PIC16C621A Microchip Technology Inc., PIC16C621A Datasheet - Page 56

• Manufacturer Part Number: PIC16C621A
• Description: Eprom-based 8-bit Cmos Microcontrollers
• Manufacturer: Microchip Technology Inc.

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