DS1642 Datasheet, PDF (11/13 Pages) Dallas Semiconductor – Nonvolatile Timekeeping RAM

AC TEST CONDITIONS
Output Load: 100pF + 1TTL Gate
Input Pulse Levels: 0.0 to 3.0V
Timing Measurement Reference Levels:
Input: 1.5V
Output: 1.5V
Input Pulse Rise and Fall Times: 5ns
DS1642
NOTES:
1) Voltages are referenced to ground.
2) Typical values are at 25C and nominal supplies.
3) Outputs are open.
4) Data retention time is at 25C.
5) Each DS1642 has a built-in switch that disconnects the lithium source until V_CC is first applied by the
user. The expected t_DR is defined as a cumulative time in the absence of V_CC starting from the time
power is first applied by the user.
6) Real-time clock modules can be successfully processed through conventional wave-soldering
techniques as long as temperature exposure to the lithium energy source contained within does not
exceed +85C. Post-solder cleaning with water washing techniques is acceptable, provided that
ultrasonic vibration is not used to prevent damage to the crystal.
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