Rainbow Electronics DS1687 User Manual
Page 37
DS1685/DS1687
37 of 38
NOTES:
1) All voltages are referenced to ground.
2) Typical values are at +25°C and nominal supplies.
3) Outputs are open.
4) Write-protection trip point occurs during power-fail prior to switchover from V
CC
to V
BAT
.
5) Applies to the AD0–AD7 pins and the SQW pin when each is in a high-impedance state.
6) The
IRQ
and
PWR
pins are open-drain outputs.
7) Measured with a load of 50pF + 1 TTL gate.
8) Wake-up kickstart timeout generated only when the oscillator is enabled and the countdown chain is
not reset.
9) V
SW
is determined by the larger of V
BAT
and V
BAUX
.
10) The DS1687 keeps time to an accuracy of ±1 minute per month during data retention time for the
period of t
DR
.
11) t
DR
is the amount of time that the internal battery can power the internal oscillator and internal
registers of the DS1687.
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.
13) I
BAT1
and I
BAT2
are measured at V
BATt
= 3.5V with recommended crystal type on X1 and X2.