DS1553 Datasheet, PDF (18/20 Pages) Maxim Integrated Products – 64kB, Nonvolatile, Year-2000-Compliant Timekeeping RAM

DS1553 64kB, Nonvolatile, Year-2000-Compliant Timekeeping RAM
AC TEST CONDITIONS
Output Load: 100 pF + 1TTL Gate
Input Pulse Levels: 0 to 3.0V
Timing Measurement Reference Levels:
Input: 1.5V
Output: 1.5V
Input Pulse Rise and Fall Times: 5ns
NOTES:
1) Voltage referenced to ground.
2) Typical values are at +25C and nominal supplies.
3) Outputs are open.
4) Battery switch over occurs at the lower of either the battery voltage or V_PF.
5) The IRQ /FT and RST outputs are open drain.
6) Data retention time is at +25C.
7) Each DS1553 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 for DIP modules as a cumulative time in the absence of V_CC starting
from the time power is first applied by the user.
8) Real-time clock modules (DIP) 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.
In addition, for the PowerCap:
a. Maxim recommends that PowerCap Module bases experience one pass through solder reflow
oriented with the label side up (“live-bug”).
b. Hand soldering and touch-up: Do not touch or apply the soldering iron to leads for more than
3 seconds. To solder, apply flux to the pad, heat the lead frame pad and apply solder. To remove
the part, apply flux, heat the lead frame pad until the solder reflow and use a solder wick to
remove solder.
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