DS1642 Datasheet, PDF (10/11 Pages) Dallas Semiconductor – Nonvolatile Timekeeping RAM

AC TEST CONDITIONS
Output Load:
Input Pulse Levels:
Timing Measurement Reference Levels:
Input: 1.5V
Output: 1.5V
Input Pulse Rise and Fall Times: 5 ns
100 pF + 1TTL Gate
0.0 to 3.0 Volts
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.
10 of 11