MIC811_05 Datasheet, PDF (1/7 Pages) Micrel Semiconductor – Microprocessor Reset Circuits

MIC811/812
MIC811/812
Microprocessor Reset Circuits
Micrel
General Description
The MIC811 and MIC812 are inexpensive microprocessor
supervisory circuits that monitor power supplies in micropro-
cessor based systems.
The function of this device is to assert a reset if either the
power supply drops below a designated reset threshold
level or /MR is forced low. Several different reset threshold
levels are available to accommodate 3V, 3.3V or 5V powered
systems.
The MIC811 has an active low /RESET output, while the
MIC812 offers an active high RESET output. The reset output
is guaranteed to remain asserted for a minimum of 140ms
after V_CC has risen above the designed reset threshold level.
Having a push-pull output stage, the MIC811/812 does not
require a pull-up resistor at the output. The MIC811/812
comes in a 4-pin SOT-143 package.
If a microprocessor voltage supervisor with an open-drain
output stage is needed, see MIC6315.
Features
• Precision voltage monitor for 3V, 3.3V or 5V power sup-
plies
• /RESET remains valid with V_CC as low as 1V
• 5µA typical supply current
• 140ms minimum reset pulse width available
• Manual reset input
• Available in 4-pin SOT-143 package
Applications
• Portable equipment
• Intelligent instruments
• Critical microprocessor power monitoring
• Printers/computers
• Embedded controllers
Typical Application
VCC
VCC
MIC81 1
RESET
MR
VCC
µP
RESET
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
September 2005
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MIC811/812