DS1818 datasheet(2/5 Pages) DALLAS

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DS1818

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OPERATION - POWER MONITOR

The DS1818 provides the functions of detecting out-of-tolerance power supply conditions and warning a

processor-based system of impending power failures. When VCC is detected as out-of-tolerance, the RST

signal is asserted. On power-up, RST is kept active for approximately 150 ms after the power supply has

reached the selected tolerance. This allows the power supply and microprocessor to stabilize before RST

is released.

BLOCK DIAGRAM (OPEN-DRAIN OUTPUT) Figure 1

APPLICATION EXAMPLE Figure 2

OPERATION - PUSHBUTTON RESET

The DS1818 provides a pushbutton switch for manual reset control. When the DS1818 is not in a reset

cycle, a pushbutton reset can be generated by pulling the RST pin low for at least 1

µs. When the

pushbutton is held low, the RST is forced active low and will remain active low for about 150 ms after

the pushbutton is released. See Figure 2 for an application example and Figure 3 for the timing diagram.

TIMING DIAGRAM: PUSHBUTTON RESET Figure 3

DS1818 Datasheet(PDF) 2 Page - Dallas Semiconductor