MIC1832
Micrel, Inc.
MIC1832
µP Supervisory Circuit
General Description
Features
The MIC1832 is a multifunction circuit which monitors mi-
croprocessor activity, external reset and power supplies in
microprocessor based systems. The circuit functions include
awatchdogtime,powersupplymonitor,microprocessorreset,
and manual pushbutton reset input.
• Power OK/Resettime delay, 250ms min.
• Watchdog timer, 150ms, 600ms, or 1.2s typical
• Precision supply voltage monitor, select between 5% or
10% of supply voltage
• Avaiable in 8-pin surface mount (SO)
• Debounced External reset input
The power supply line is monitored with a comparator and
an internal voltage reference. /RST is forced low when an
out-of-tolerance condition exists and remains asserted for
• Low supply current, <18µA typical
Applications
• Autimotive systems
• Intelligent systems
• Critical microprocessor power monitoring
• Battery powered computers
• Controllers
at least 250ms after V rises above the threshold voltage
CC
(2.55V or 2.88V). The /RST pin will remain logic low with
V
as low as 1.4V.
CC
The Watchdog input (/ST) monitors µP activity and will as-
sert /RST if no µP activity has occurred with in the watchdog
timeout period. The watchdog timeout period is selectable
with nominal period of 150, 600, 1200 milliseconds.
Ordering Information
Part Number
Pb-Free
Temperature Range
Package
Standard
MIC1832N
MIC1832M
MIC1832NY
MIC1832MY
–40ºC to +85ºC
–40ºC to +85ºC
8-Pin PDIP
8-Pin SOIC
Typical Application
V
CC
V
CC
TD
V
CC
MIC1832
µP
PBRST
ST
RST
GND
I/O
RESET
TOL
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
January 2006
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MIC1832