DS1685 datasheet(33/39 Pages) DALLAS

33 / 39 page

DS1685/DS1687 3V/5V Real-Time Clocks

33 of 39

WAKE-UP/KICKSTART TIMING

Note 1:

All voltages are referenced to ground.

Note 2:

Typical values are at +25°C and nominal supplies.

Note 3:

Outputs are open.

Note 4:

Applies to the AD0–AD7 pins and the SQW pin when each is in a high-impedance state.

Note 5:

The

IRQ and PWR pins are open-drain outputs.

Note 6:

Measured with a load of 50pF + 1 TTL gate.

Note 7:

Wake-up kickstart timeout generated only when the oscillator is enabled and the countdown chain is not reset.

Note 8:

VSW is determined by the larger of VBAT and VBAUX.

Note 9:

The DS1687 keeps time to an accuracy of ±1 minute per month at 25°C during data retention time for the period of tDR.

Note 10: tDR is the amount of time that the internal battery can power the internal oscillator and internal registers of the DS1687

at 25°C.

Note 11: RTC Encapsulate DIP 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, if ultrasonic vibration is not used.

Note 12: IBAT1 and IBAT2 are measured at VBAT or VBAUX = 3.5V and with recommended crystal type on X1 and X2.

*THIS CONDITION CAN OCCUR WITH THE 3V DEVICE.

NOTE: TIME INTERVALS SHOWN ABOVE ARE REFERENCED IN WAKE-UP/KICKSTART SECTION.

DS1685 Datasheet(PDF) 33 Page - Dallas Semiconductor