PRODUCT DATABOOK 1996/1997
MC33064/MC34064
U
N D E RV O LTA G E
S
E N S I N G
C
I R C U I T
P
R O D U C T I O N
D
A T A
S
H E E T
T Y P I C A L A P P L I C AT I O N C I R C U I T S
FIGURE 15.
— LOW VOLTAGE MICROPROCESSOR RESET
V
IN
RESET
POWER
SUPPLY
C
DLY
FIGURE 16.
— SWITCHING THE LOAD OFF WHEN
BATTERY REACHES BELOW 4.3V
R
MICROPROCESSOR
CIRCUIT
V
IN
1.2 V
REF
LOAD
RESET
A time delayed reset can be accomplished with the addition of C
DLY
.
For systems with extremely fast power supply rise times (< 500ns) it
is recommended that the RC
DLY
time constant be greater than 5.0µs.
V
TH(MPU)
is the microprocessor reset input threshold.
1.2 V
REF
t
DLY
= R C
DLY
In
1
V
1 -
TH(MPU)
V
IN
FIGURE 17.
— VOLTAGE MONITOR
FIGURE 18.
— MOSFET LOW VOLTAGE GATE DRIVE PROTECTION
V
CC
270
V
IN
RESET
R
L
SMP60N03-10L
1.0k
V
IN
POWER
SUPPLY
4.3V
RESET
1.2 V
REF
1.2 V
REF
Overheating of the logic level power MOSFET due to insufficient gate
voltage can be prevented with the above circuit. When the input signal is
below the 4.6 volt threshold of the MC34064, its output grounds the gate
of the L
2
MOSFET.
Copyright © 1999
Rev. 1.3a 9/17/2004
9
MICROSEMI [ MICROSEMI CORPORATION ]
