PIC16C62X
FIGURE 9-12: EXTERNAL POWER-ON
RESET CIRCUIT (FOR SLOW
VDD POWER-UP)
FIGURE 9-13: EXTERNAL BROWN-OUT
PROTECTION CIRCUIT 1
VDD
VDD
33k
VDD
VDD
10k
MCLR
D
R
40k
R1
PIC16C62X
MCLR
PIC16C62X
C
Note 1: External power-on reset circuit is required
only if VDD power-up slope is too slow.
The diode D helps discharge the capaci-
tor quickly when VDD powers down.
Note 1: This circuit will activate reset when VDD
goes below (Vz + 0.7V) where
Vz = Zener voltage.
2: Internal Brown-out Reset circuitry
should be disabled when using this cir-
cuit.
2: < 40 kΩ is recommended to make sure
that voltage drop across R does not vio-
late the device’s electrical specification.
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 break-
down due to Electrostatic Discharge
FIGURE 9-14: EXTERNAL BROWN-OUT
PROTECTION CIRCUIT 2
VDD
(ESD) or Electrical Overstress (EOS).
VDD
R1
Q1
MCLR
R2
40k
PIC16C62X
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
= 0.7 V
VDD x
R1 + R2
2: Internal brown-out reset should be dis-
abled when using this circuit.
3: Resistors should be adjusted for the
characteristics of the transistor.
DS30235G-page 54
Preliminary
1998 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
