Rainbow-electronics DS17287 Manual do Utilizador descarregar pdf (Página 34)

DS17285/DS17287

34 of 38

BURST MODE TIMING WAVEFORM

NOTES:

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

2) Outputs are open.

3) Write-protection trip point occurs during power-fail prior to switchover from V

to V

BAT

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

5) The IRQ and PWR pins are open-drain.

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

7) Wake-up kickstart timeout generated only when the oscillator is enabled and the countdown chain is

not reset.

8) V

is determined by the larger of V

BAT

and V

BAUX

9) The DS17287 keeps time to an accuracy of ±1 minute per month during data retention time for the

period of t

10) t

is the amount of time that the internal battery can power the internal oscillator and internal

registers of the DS17287.

11) I

BAT1

and I

BAT2

are measured at V

BAT

= 3.5V, with a 32.768kHz crystal attached to X1 and X2

(DS17285).

12) RTC 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.

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Rainbow-electronics DS17287 Manual do Utilizador Página 34