DS1233A_09 Datasheet, PDF (2/5 Pages) Dallas Semiconductor – 3.3V EconoReset

OPERATION — PUSHBUTTON RESET
DS1233A
The DS1233A provides for a pushbutton switch to be connected to the RST output pin. When the
DS1233A is not in a reset cycle, it continuously monitors the RST signal for a low-going edge. If an edge
is detected, the DS1233A will debounce the switch by pulling the RST line low. After the internal timer
has expired, the DS1233A will continue to monitor the RST line. If the line is still low, the DS1233A will
continue to monitor the line looking for a rising edge. Upon detecting a release, the DS1233A will force
the RST line low and hold it low for 350ms.
NOTE:
For proper operation with an external pushbutton, a capacitor between 100pF and 0.01F must be
connected between RST and ground. In applications where additional reset current is required, a
minimum capacitance of 500 pF should be used, along with a parallel external pull-up resistor of 1k
minimum.
BLOCK DIAGRAM Figure 1
APPLICATION EXAMPLE Figure 2
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