DS14285 Datasheet, PDF (22/25 Pages) Dallas Semiconductor – Real Time Clock with NV RAM Control

NOTES:
1. All voltages are referenced to ground.
2. All outputs are open.
3. The MOT pin has an internal pull-down of 20 kΩ.
DS14285/DS14287
4. The CEI pin has an internal pull-up of 50 kΩ.
5. Applies to the AD0-AD7 pins, the IRQ pin, and the SQW pin when each is in the high impedance
state.
6. The IRQ pin is open drain. The interrupt and the internal clock continue to run regardless of the level
of VCC. However, it is important to insure that the pullup resistor used with the interrupt pin is never
pulled up to a value which is greater than VCC + 0.3V. As VCC falls below approximately 3.0 volts,
a power switching circuit turns the lithium energy source on to maintain the clock and timer data
functionality.
7. I_CCO =100 mA, V_CC > V_BAT.
8. I_CCO =100 µA, V_CC < V_BAT.
9. Measured with a load as shown in Figure 5.
10. Expected data retention is based on using an external SRAM with a data retention current of less than
1 µA at 25°C.
11. Z_CE is an average input-to-output impedance as the input is swept from ground to V_CCI and less than 4
mA is forced through Z_CE.
12. Real-Time Clock Modules such as the DS14287 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.
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