ASM1832
器件描述：3.3V UP Power Supply Monitor and Reset Circuit
器件厂商：ALSC [Alliance Semiconductor Corporation]
厂商主页：http://www.alsc.com/
文件大小：259.58KB，共9页
Sponsor by e络盟器件资料摘要：
ASM1832
Alliance Semiconductor
2575 Augustine Drive . Santa Clara, CA 95054 . Tel: 408.855.4900 . Fax: 408.855.4999 . www.alsc.com
Notice: The information in this document is subject to change without notice
rev 1.5
3.3V µP Power Supply Monitor and Reset Circuit
February 2005
General Description
The ASM1832 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. RESET and RESET outputs are
push-pull.
A precision temperature-compensated reference and
comparator circuits monitor the 3.3V, 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 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%.
A debounced manual reset input, PBRST, activates the reset
outputs for a minimum period of 250ms. There is a watchdog
timer to stop and restart a microprocessor that is “hung-up”.
The watchdog timeouts periods are selectable: 150ms, 610ms,
and 1200ms. If the ST input is not strobed LOW before the
time-out period expires, a reset is generated.
Devices are available in 8-pin PDIP, 8-pin SO and compact 8-
pin MicroSO packages.
Key Features
• 3.3V supply monitor
• Push-pull output
• Selectable watchdog period
• Debounce manual push-button reset input
• Precision temperature-compensated voltage reference
and comparator.
• Power-up, power-down and brown out 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 Micro SO packages
• Wide operating temperature -40°C to +85°C
Applications
• Microprocessor systems
• Computers
• Controllers
• Portable instruments
• Automotive systems
Typical Operating Circuit Block Diagram
Tolerance Selection
Reference
Push Button
Debounce
Voltage Sense
Comparator
Reset &
Watchdog Timer
Watchdog
Transition Detector
+
-
V
CC
TOL
PBRST
TD
ST
RESET
RESET
40KΩ
V
CC
V
CC
V
CC
GND
ASM1832
ST
RESET
RESET
I/O
µP
ASM1832
GND TOLTD
3.3V
Alliance Semiconductor
2575 Augustine Drive . Santa Clara, CA 95054 . Tel: 408.855.4900 . Fax: 408.855.4999 . www.alsc.com
Notice: The information in this document is subject to change without notice
rev 1.5
3.3V µP Power Supply Monitor and Reset Circuit
February 2005
General Description
The ASM1832 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. RESET and RESET outputs are
push-pull.
A precision temperature-compensated reference and
comparator circuits monitor the 3.3V, 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 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%.
A debounced manual reset input, PBRST, activates the reset
outputs for a minimum period of 250ms. There is a watchdog
timer to stop and restart a microprocessor that is “hung-up”.
The watchdog timeouts periods are selectable: 150ms, 610ms,
and 1200ms. If the ST input is not strobed LOW before the
time-out period expires, a reset is generated.
Devices are available in 8-pin PDIP, 8-pin SO and compact 8-
pin MicroSO packages.
Key Features
• 3.3V supply monitor
• Push-pull output
• Selectable watchdog period
• Debounce manual push-button reset input
• Precision temperature-compensated voltage reference
and comparator.
• Power-up, power-down and brown out 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 Micro SO packages
• Wide operating temperature -40°C to +85°C
Applications
• Microprocessor systems
• Computers
• Controllers
• Portable instruments
• Automotive systems
Typical Operating Circuit Block Diagram
Tolerance Selection
Reference
Push Button
Debounce
Voltage Sense
Comparator
Reset &
Watchdog Timer
Watchdog
Transition Detector
+
-
V
CC
TOL
PBRST
TD
ST
RESET
RESET
40KΩ
V
CC
V
CC
V
CC
GND
ASM1832
ST
RESET
RESET
I/O
µP
ASM1832
GND TOLTD
3.3V