The LM809 and LM810 microprocessors 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 and LM810 are to monitor the VCC supply
voltage, and assert a reset signal whenever this voltage declines below the factory-programmed
reset threshold. The reset signal remains asserted for 240 ms after VCC
rises above the threshold. The LM809 has an active-low RESET output, while
the LM810 has an active-high RESET output.
Seven standard reset voltage options are available, suitable for monitoring 5-V, 3.3-V,
and 3-V supply voltages.
With a low supply current of only 15 µA, the LM809 and LM810 are ideal for use in
portable equipment.
