SS8039 SSC [Silicon Standard Corp.], SS8039 Datasheet - Page 5

• Manufacturer Part Number: SS8039
• Description: Microprocessor Voltage Monitor with Manual Reset
• Manufacturer: SSC [Silicon Standard Corp.]

Rev.2.02 1/06/2004
Pin Description
Detailed Description
A microprocessor’s (µP’s) reset input starts the µP in a
known state. The SS8039L and SS8039H assert reset
to prevent code-execution errors during power-up,
power-down, or brownout conditions. They assert a reset
signal whenever the V
preset threshold, keeping it asserted for at least 140ms
after V
The SS8039L/ SS8039H have a push-pull output stage.
The manual reset input (MR) can also initiate a reset.
See the Manual Reset Input Section.
Manual Reset Input
Many µP-based products require manual reset capability
allowing the operator, a test technician, or external logic
circuitry to initiate a reset. A logic low on
reset. Reset remains asserted while
high. This input has an internal 20k
it can be left open if it is not used.
TTL or CMOS-logic levels, or with open-drain / collector
outputs. Connect a normally open momentary switch
from
external debounce circuitry is not required. If
driven from long cables or if the device is used in a
noisy environment, connecting a 0.1µF capacitor from
the Reset Active Timeout Period (t
PIN
MR
1
2
3
4
to ground provides additional noise immunity.
MR
CC
has risen above the reset threshold.
(SS8039L)
(SS8039H)
to GND to create a manual-reset function;
RESET
NAME
RESET
GND
V
MR
CC
CC
supply voltage declines below a
Ground
rises above the reset threshold.
RESET Output remains high while V
rises above the reset threshold.
Manual Reset Input. A logic low on MR asserts reset. Reset remains asserted as long as MR is
low and for
resistor. It can be driven from a TTL or CMOS-logic line, or shorted to ground with a switch. Leave
open if unused.
Supply Voltage (+5V, +3.3V, +3.0V)
RESET Output remains low while V
MR
RP
) after
at
MR
pull-up resistor, so
www.SiliconStandard.com
can be driven with
least 140ms after MR returns high, This active-low input has an internal 20k
is low, and for
MR
MR
asserts
returns
MR
is
CC
CC
is below the reset threshold, and for at least 140ms after V
is below the reset threshold, and for at least 140ms after V
Figure2.
FUNCTION
Fig.1 Maximum Transient Duration Without
Causing a Reset Pulse vs. Reset Comparator Overdrive
600
500
400
300
200
100
0
1
RESET
Reset Comparator Overdrive, V
SS8039
Valid to V
V
V
GND
GND
CC
CC
10
RESET
RESET
CC
= Ground Circuit
TH
100
-V
R1
R1
100k
100k
CC
(mV)
SS8039
pull- up
1000
CC
CC
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