By Maxim Integrated 61
The Maxim Integrated DS1682 and DS1683 are integrated elapsed-time recorders containing a factory-calibrated, low-temperature-coefficient, RC time base that eliminates the need for an external crystal. Using EEPROM technology to maintain data in the absence of power, the devices require no backup power source. The DS1683 detects and records the number of falling edge transitions on the EVENT pin as well as the total cumulative time that the EVENT pin is held high. The DS1682 detects and records the number of events on the EVENT pin and the total cumulative event time since the DS1682 was last reset to 0.
The ALARM pin alerts the user when the total time accumulated equals or exceeds the user-programmed alarm value, or when the total number of events equals or exceeds the user-programmed alarm value. The polarity of the open-drain ALARM pin can be programmed to either drive low or become high impedance upon an alarm condition. The DS1682 and DS1683 are ideal for applications that monitor the total amount of time that a device has been in operation and/or the number of uses since inception service, repair, or last calibration.