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Features
Precise monitoring of 2.5V, 3.3V, and 5V supply voltages
Fully specified over temperature
Industrial: −40°C to +85°C
Extended: −40°C to +125°C
100 ms minimum Power-On Reset pulse width, 190 ms typical:
Active-Low
^RESET Output (LM3722)
Active-High RESET Output (LM3723)
Active-Low
^RESET Open Drain Output (LM3724)
Guaranteed
^RESET Output valid for VCC
≥ 1V
Low Supply Current, 6µA typical
Power supply transient immunity
Compatible with MAX811/812 applications
Description The LM3722/LM3723/LM3724 microprocessor supervisory circuits monitor the power supplies in microprocessor and digital systems.
They provide a reset to the microprocessor during power-up, power-down, brown-out conditions, and manual reset.
The LM3722/LM3723/LM3724 asserts a reset signal whenever the supply decreases below the factory-programmed reset threshold.
Reset will be asserted for at least 100ms even after VCC rises above the reset threshold.
The LM3722 has an active-low
^RESET push-pull output. The LM3723 has an active-high RESET push-pull output. The LM3724 has an active-low open-drain
^RESET output.
Three standard reset voltage options are available, suitable for monitoring 5V, 3.3V, and 2.5V supply voltages. Additional
reset voltages are also available; contact National Semiconductor for details.
With a low supply current of only 6µA, the LM3722/LM3723/LM3724 are ideal for use in portable equipment. The LM3722/LM3723/LM3724
are available in the 5-pin SOT23 package.
Applications
Microprocessor Systems
Computers
Controllers
Intelligent Instruments
Portable/Battery-Powered Equipment
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