NSC LM809M3X-4.00, LM809M3X-3.08, LM809M3X-2.93, LM809M3X-2.63, LM809M3-4.38 Datasheet
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LM809/LM810
3-Pin Microprocessor Reset Circuits
LM809/LM810 3-Pin Microprocessor Reset Circuits
September 1999
General Description
The LM809/810 microprocessor supervisory circuits can be
used to monitor the power supplies in microprocessor and
digital systems. They provide a reset to the microprocessor
during power-up, power-down and brown-out conditions.
The function of the LM809/810 is to monitor the V
voltage, and assert a reset signal whenever this voltage declines below the factory-programmed reset threshold. The
reset signal remains asserted for 240ms after V
above the threshold. The LM809 has an active-low RESET
output, while the LM810 has an active-high RESET output.
Six standard reset voltage options are available, suitable for
monitoring 5V, 3.3V, and 3V supply voltages.
With a low supply current of only 15µA, the LM809/810 are
ideal for use in portable equipment. The LM809/LM810 are
available in the 3-pin SOT23 package.
CC
supply
CC
Features
n Precise monitoring of 3V, 3.3V, and 5V supply voltages
n Superior upgrade to MAX809/810
n Fully specified over temperature
n 140ms min. Power-On Reset pulse width, 240ms typical
Active-low RESET Output (LM809)
Active-high RESET Output (LM810)
n Guaranteed RESET Output valid for V
rises
n Low Supply Current, 15µA typ.
n Power supply transient immunity
Applications
n Microprocessor Systems
n Computers
n Controllers
n Intelligent Instruments
n Portable/Battery-Powered Equipment
n Automotive
Typical Application Circuit Connection Diagram
( ) are for LM810
DS101057-1
≥1V
CC
DS101057-2
© 1999 National Semiconductor Corporation DS101057 www.national.com
Ordering Information
Reset Threshold
(V)
LM809 Supplied as
1000 units, tape & reel
LM809 Supplied as
3000 units, tape & reel
Package
Top Mark
Package Type NSC Package
4.63 LM809M3-4.63 LM809M3X-4.63 S8B
4.38 LM809M3-4.38 LM809M3X-4.38 S7B
4.00 LM809M3-4.00 LM809M3X-4.00 S6B
3.08 LM809M3-3.08 LM809M3X-3.08 S5B
SOT23-3 M03B
2.93 LM809M3-2.93 LM809M3X-2.93 S4B
2.63 LM809M3-2.63 LM809M3X-2.63 S3B
Reset Threshold
(V)
LM810 Supplied as
1000 units, tape & reel
LM810 Supplied as
3000 units, tape & reel
Package
Top Mark
Package Type NSC Package
4.63 LM810M3-4.63 LM810M3X-4.63 SEB
4.38 LM810M3-4.38 LM810M3X-4.38 SDB
4.00 LM810M3-4.00 LM810M3X-4.00 SCB
3.08 LM810M3-3.08 LM810M3X-3.08 SBB
SOT23-3 M03B
2.93 LM810M3-2.93 LM810M3X-2.93 SAB
2.63 LM810M3-2.63 LM810M3X-2.63 S9B
Custom voltages and improved accuracies are available, subject to minimum orders. Contact your local National Semiconductor Sales Office for information.
Pin Description
PIN NAME FUNCTION
1 GND Ground reference
RESET (LM809)
2
RESET (LM810)
3V
CC
Active-low output. RESET remains low while VCCis below the reset threshold, and
for 240ms after VCCrises above the reset threshold.
Active-high output. RESET remains high while V
for 240ms after V
rises above the reset threshold.
CC
is below the reset threshold, and
CC
Supply Voltage (+5V, +3.3V, or +3.0V)
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