ASM1232LP Datasheet, PDF (1/12 Pages) Alliance Semiconductor Corporation – 5V uP Power Supply Monitor and Reset Circuit

ASM1232LP, ASM1232LPS
5 V mP Power Supply
Monitor and Reset Circuit
Description
The ASM1232LP/LPS is a fully integrated microprocessor
Supervisor. It can halt and restart a “hung−up” microprocessor, restart
a microprocessor after a power failure. It has a watchdog timer and
external reset override.
A precision temperature−compensated reference and comparator
circuits monitor the 5 V, V_CC input voltage status. During power−up or
when the V_CC power supply falls outside selectable tolerance limits,
both RESET and RESET become active. When V_CC rises above the
threshold voltage, the reset signals remain active for an additional
250 ms minimum, allowing the power supply and system
microprocessor to stabilize. The trip point tolerance signal, TOL,
selects the trip level tolerance to be either 5% or 10%.
Each device has both a push−pull, active HIGH reset output and an
open drain active LOW reset output. A debounced manual reset input,
PBRST, activates the reset outputs for a minimum period of 250 ms.
There is a watchdog timer to stop and restart a microprocessor that is
“hung−up”. The watchdog timeouts periods are selectable: 150 ms,
610 ms and 1200 ms. If the ST input is not strobed LOW before the
time−out period expires, a reset is generated.
Devices are available in 8−pin DIP, 16−pin SO and compact 8−pin
MicroSO packages.
Features
• 5 V Supply Monitor
• Selectable Watchdog Period
• Debounce Manual Push−button Reset Input
• Precision Temperature−compensated Voltage Reference and
Comparator
• Power−up, Power−down and Brown Out Detection
• 250 ms Minimum Reset Time
• Active LOW Open Drain Reset Output and Active HIGH Push−pull
Output
• Selectable Trip Point Tolerance: 5% or 10%
• Low−cost Surface Mount Packages: 8−pin/16−pin SO, 8−pin DIP and
8−pin Micro SO Packages
• Wide Operating Temperature −40°C to +85°C (N Suffixed Devices)
Applications
• Microprocessor Systems
• Computers
• Controllers
• Portable Equipment
• Intelligent Instruments
• Automotive Systems
http://onsemi.com
PDIP−8
P SUFFIX
CASE 646AA
MICRO−8
U SUFFIX
CASE 846AA
SOIC−8
S SUFFIX
CASE 751BD
SOIC−16
S SUFFIX
CASE 751BG
PIN CONFIGURATIONS
1
PBRST
V_CC
TD
ST
TOL
RESET
GND
DIP/SO/MicroSO
(Top View)
1
NC
PBRST
NC
TD
NC
TOL
NC
GND
SO
(Top View)
RESET
NC
V_CC
NC
ST
NC
RESET
NC
RESET
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 12 of this data sheet.
© Semiconductor Components Industries, LLC, 2011
1
August, 2011 − Rev. 3
Publication Order Number:
ASM1232LP/D