IMP1832
P
OWER
M
ANAGEMENT
Key Features
3.3V µP Power Supply
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Pin compatible with the Dallas Semiconductor
DS1832
— Over 40% lower supply current
Monitor and Reset Circuit
– Selectable Trip-Point Tolerance and
Watchdog Period
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3.3V supply monitor
Push-pull output
– Push-Button Reset
Selectable watchdog period
Debounce manual push-button reset input
Precision temperature-compensated voltage
reference and comparator
Power-up, power-down and brownout detection
250ms minimum reset time
Active LOW and HIGH reset signal
Selectable trip point tolerance: 10% or 20%
Low-cost 8-pin DIP/ SO and 8-pin MicroSO
packages
– Push-Pull Reset Outputs
The IMP1832 microprocessor supervisor can halt and restart a “hung-
up” or “stalled” microprocessor, restart a microprocessor after a power
failure, and debounce a manual push-button microprocessor reset
switch. The IMP1832 features over 40% lower supply current than the
pin compatible Dallas Semiconductor DS1832.
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Precision temperature compensated reference and comparator circuits
monitor the 3.3V, V input voltage. During power-up or when the V
CC
CC
power supply falls outside selectable tolerance limits, both RESET and
RESET become active. When V rises above the threshold voltage, the
CC
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Wide operating temperature –40°C to +85°C
reset signals remain active for an additional 250ms minimum, allowing
the power supply and system microprocessor to stabilize. The trip point
tolerance signal, TOL, selects the trip level tolerance to be either 10- or
20-percent.
Also included is a watchdog timer to stop and restart a
microprocessor that is “hung-up”. Three watchdog time-
out periods are selectable: 150ms, 610ms and 1,200ms. If the
ST input is not strobed LOW before the time-out period
expires, a reset is issued.
RESET and RESET outputs are push-pull.
A debounced manual reset input, PBRST, activates the reset outputs for
a minimum period of 250ms.
Devices are available in 8-pin DIP, 8-pin SO and compact
8-pin MicroSO packages.
Block Diagram
VCC
8
IMP1832
VCC
3
6
10%/20% Tolerance
TOL
RESET
Selection
+
VCC
Reference
–
VCC
5
RESET
40k
1
2
7
Push Button
Debounce
PBRST
TD
Watchdog
Timebase Selection
Reset &
Watchdog Timer
Watchdog
Transition Detector
ST
4
1832_02.eps
GND
©
1999 IMP, Inc.
408-432-9100/ www.impweb.com
1
IMP [ IMP, INC ]
